The Federal Aviation Administration is investigating a Monday failure of air traffic controllers' radio at Denver International Airport — one of the world's busiest airports, per an FAA statement.

Why it matters: It's the latest in a string of alarming tech and safety lapses nationwide that's shaking confidence in the U.S. aviation network.

The latest: Around 1:50pm Monday, a segment of the Denver Air Route Traffic Control Center lost communications for approximately 90 seconds when both primary transmitters went down, the FAA confirmed Thursday in a statement to Axios Denver.

• Air traffic controllers switched to an alternate frequency to direct planes.
• The FAA said all aircraft remained safely separated and operations weren't affected.
• Still, Denver7 reports as many as 20 aircraft flying toward DIA couldn't reach controllers for up to six minutes.

By the numbers: Assuming the planes were traveling at a groundspeed of 200 knots, they would have covered 20 miles without ATC contact in those six minutes.

Between the lines: As of 2023, DIA's air traffic control tower was short seven controllers, and the facility that guides planes in the surrounding area was down 10, a recent FAA report shows.

The big picture: The incident adds Denver to a growing list of major U.S. airports grappling with technology failures in the air traffic control system — an increasingly urgent concern amid a post-pandemic travel boom.

• The FAA has blamed recent mishaps on aging infrastructure and critical staffing shortages.
• Last week, U.S. Transportation Secretary Sean Duffy unveiled a multi-billion-dollar modernization plan aimed at upgrading outdated systems and improving reliability.

What they're saying: On Wednesday, DIA officials told Axios Denver: "We enjoy a strong partnership with the FAA and have full confidence in knowing that they put safety first in everything they do related to operations" at DIA.

• They declined to comment on Duffy's plan.

What's next: The FAA emphasized its findings are preliminary and said the investigation is ongoing.

Go deeper: Colorado's significant air traffic controller shortages

Editor's note: This is a breaking story. Please check back for additional details.

Boulder won its bid to host the iconic Sundance Film Festival beginning in 2027.

Why it matters: Hosting Sundance — the largest independent film festival in the U.S. — will be a major moneymaker and tourism attraction for Boulder and the state.

By the numbers: A recent economic impact report on the 2024 Sundance Film Festival in Utah revealed the event:

• Created 1,730 jobs for residents;
• Generated $69.7 million in wages;
• Amounted to $132 million in gross domestic product;
• Brought in almost $14 million in state and local tax revenue.

The latest: The Sundance Board voted Thursday to move the festival out of Park City, Utah — where it's been held for the past four decades.

• Cincinnati was the other finalist in the list of potential future host cities.

What they're saying: "Boulder is an art town, tech town, mountain town, and college town. It is a place where the Festival can build and flourish," Sundance Institute acting CEO Amanda Kelso said in a statement Thursday.

• In response to the announcement, Colorado Gov. Jared Polis said the state can "expect even more jobs, a huge benefit for our small businesses including stores and restaurants."

The intrigue: To boost Boulder's odds, state lawmakers have been pushing a bill to create new tax credits to encourage the Sundance Film Festival to relocate to Colorado.

• The incentives include $34 million over the next decade or $3-$5 million per year, for a film festival that sells more than 100,000 tickets and attracts tens of thousands of out-of-state attendees.

Catch up quick: The festival's contract with Park City expires after the 2026 event, which prompted local officials to begin soliciting relocation bids last April.

• While the full list of contenders was not released, known bidders included Minneapolis, San Francisco and Savannah, Georgia.
• Notably, Denver did not throw its hat in the ring.

What's next: The festival will be hosted in Boulder through 2037 after officials signed a 10-year deal, Variety reports.

• "This is the beginning of a bold, new journey as we invite everyone to be part of our community and to be entertained and inspired," Kelso said. "We can't imagine a better fit than Boulder."

If you want more Boulder news, subscribe to Axios Boulder, launching this spring.

The arrest of a longtime immigrant rights activist — who made national headlines when she took sanctuary in a Denver church during President Trump's first term — has rattled advocates and immigrants across the country.

Why it matters: Despite the Trump administration's pledge to focus on the "worst of the worst," Jeanette Vizguerra joins a growing list of nonviolent figures targeted in the immigration crackdown.

• Immigrant rights groups worry a string of arrests signals a new phase in immigration enforcement and an effort to silence critics.

Driving the news: Vizguerra was on break from her job at a Target store near Denver on Monday when U.S. Immigration and Customs Enforcement agents detained her, according to Jordan Garcia, an advocate with the American Friends Service Committee.

• Garcia told the New York Times that agents said to Vizguerra: "We finally got you."
• In a statement to Axios Denver, an ICE spokesperson defended Vizguerra's arrest, calling her "a convicted criminal alien ... who has a final order of deportation issued by a federal immigration judge."

Flashback: Vizguerra, a Mexican citizen who entered the U.S. without authorization in 1997, has lived in legal limbo for decades.

• She became a national symbol of resistance in 2017 when she moved into a Denver church basement with her three youngest children to avoid deportation.
• Time magazine named her one of the world's most influential people that year.
• In 2021, the Biden administration granted her a one-year deportation stay.

The big picture: Vizguerra's case follows other high-profile detentions of nonviolent people by federal immigration agents.

By the numbers: About 50% of people in ICE custody have no prior criminal conviction or pending charges, according to agency data updated through March 7.

• Homeland Security secretary Kristi Noem also said fewer than half of the department's 33,000 arrests in the first 50 days since the start of Trump's second term were of people with criminal records.

Zoom in: Pro-Palestinian activist Mahmoud Khalil was arrested by immigration authorities this month despite being a legal permanent resident.

• Badar Khan Suri, a Georgetown University graduate student from India who was teaching at the D.C. institution on a student visa, was detained by immigration authorities this week and accused of "spreading Hamas propaganda." His lawyers say he's being "punished" because his U.S. citizen wife is of Palestinian heritage, per Politico.
• Canadian actress Jasmine Mooney reported being "in chains" after ICE detained her for 12 days over visa paperwork issues before allowing her return to Vancouver.

Between the lines: ICE under Trump has also increasingly targeted immigrants with legal status or without deportation orders.

• Rhode Island doctor Rasha Alawieh, who according to court documents is a citizen of Lebanon who holds an H-1B visa, was deported last week upon her arrival at a Boston airport.
• Camila Muñoz, a Peruvian woman married to a U.S. citizen who was in the process of getting permanent legal status, was detained while returning from a trip to Puerto Rico. Muñoz previously overstayed a visa.

State of play: Vizguerra's arrest has sparked protests and condemnation from Colorado's Democratic congressional delegation, Gov. Jared Polis and Denver Mayor Mike Johnston.

• Johnston characterized the arrest as "Putin-style persecution of political dissidents" targeting a working mother dedicated to helping other undocumented immigrants.

The other side: Spokespeople from the U.S. Department of Homeland Security and the White House did not immediately respond to Axios' request for comment.

What we're watching: Vizguerra's lawyers have filed a challenge in federal court. She remains detained at an ICE facility in the Denver suburb of Aurora.

• In Khalil's case, a New York federal judge transferred his legal battle to New Jersey, where his legal team is fighting for his release.

Go deeper: Tracking the foreign nationals detained by ICE as tourists or U.S. residents

• Germany warns its travelers of tougher U.S. immigration enforcement

Editor's note: This article has been updated to include details of the detention of Georgetown University researcher Badar Khan Suri.

About 1 in 15 U.S. adults has been on scene at a mass shooting, a new University of Colorado Boulder study published in JAMA Network Open reveals.

Why it matters: The study underscores the pervasiveness of gun violence in the U.S. and the increasing likelihood that everyday Americans could be caught in the crossfire.

The big picture: "Our findings lend credence to the idea of a 'mass shooting generation,'" senior author David Pyrooz said in a statement.

• "People who grew up in the aftermath of Columbine have these unique experiences that are really distinguishable from the older population," he said.

By the numbers: About 7% of 10,000 U.S. adults surveyed online in January 2024 said they had been present at a mass shooting — defined as an incident where four or more people were shot.

• 2% reported being injured, whether by gunfire, by shrapnel or in the chaos of people fleeing.
• Among those uninjured, about 75% said they suffered psychological distress.
• More than half of those who had witnessed a mass shooting said it happened within the last decade.

Between the lines: Gen Z and men were at the highest risk, the study found.

• And for most survivors, the violence hit close to home. More than three-fourths of mass shootings took place in their own communities.

Zoom in: Colorado has experienced at least 61 mass shootings in the last 10 years, killing 82 people and injuring 246, according to data on the state health department's website.

• In 2023 alone, there were 16 mass shootings in the state — the highest in at least a decade, according to the Gun Violence Archive.
• Data for 2024 is not readily available.

What they're saying: "It's not a question of if one will occur in your community anymore, but when," Pyrooz said. "We need to have stronger systems in place to care for people in the aftermath of this tragic violence."

The other side: Despite the grim reality, mass shootings actually declined nationwide last year — dropping nearly 25% from 2023.

• The U.S. reported 503 mass shootings in 2024, down from 659 the year before, per the Gun Violence Archive.
• The decrease could be attributable to the waning social and economic upheavals set off by the coronavirus pandemic, Giffords Law Center's research director Kelly Drane told Axios last year.

What we're watching: Colorado lawmakers are considering a controversial gun control bill that would restrict the sale of most semiautomatic firearms, like the one used by the Boulder King Soopers shooter in 2021.

• The legislation — sponsored by Sen. Tom Sullivan, a Centennial Democrat whose son was killed in the 2012 Aurora theater shooting — has been amended more than a dozen times, Colorado Politics reports.

Republican legislators called for a Department of Justice investigation into Democratic mayors they accused Wednesday at a House committee hearing of leading sanctuary cities.

The big picture: A "sanctuary city" label could have major consequences, with Republicans threatening to pull federal funding and, in Denver Mayor Mike Johnston's case, pursue criminal charges.

• President Trump signed an executive order the day he was inaugurated calling for federal grants to sanctuary cities to be cut.

Driving the news: Although federal courts have blocked Trump's order, Chicago Mayor Brandon Johnson, Boston Mayor Michelle Wu and New York Mayor Eric Adams were targeted in a five-hour-plus House Oversight Committee hearing in Washington, D.C. Wednesday.

• Committee Chair James Comer (R-Ky.) defined sanctuary cities as those that "violate federal immigration law by protecting criminal aliens" and those that "refuse to cooperate with federal immigration enforcement efforts."

What they're saying: Rep. Anna Paulina Luna (R-Fla.) accused the mayors of "harming the American people."

• Johnson responded: "We comply with all laws, local, state and federal."

Friction point: The Democratic mayors and Republican lawmakers primarily disagree on the circumstances that should compel local law enforcement to cooperate with U.S. Immigration and Customs Enforcement agents.

• All the mayors said they work with ICE when presented with a criminal warrant.
• Republican legislators, however, say the cities must additionally honor ICE detainers, which require holding arrestees longer than legally allowed.
• Several municipalities face lawsuits for using detainers when detainees were determined to be U.S. citizens.

Zoom in: Adams is suing the Trump administration for funding for asylum seekers.

• He faces federal bribery and fraud charges the DOJ is fighting to have dropped so Adams can comply with Trump's immigration policies.
• He agreed to honor detainer requests.

More from Axios:

• Republicans push to investigate sanctuary city mayors
• Boston mayor grilled as misinformation flies at sanctuary cities hearing
• Congress threatens Denver mayor with jail over immigration policies

The IRS started laying off employees on Thursday, just as tax season kicks into high gear.

Why it matters: The terminations, reportedly of 6,000 relatively new workers at the agency, are part of President Trump's broader purge of the federal workforce.

Zoom in: Layoffs began Thursday for dozens of Denver-based Internal Revenue Service employees.

• Between 120 and 150 Denver IRS employees are on the chopping block, National Treasury Employees Union Chapter 32 president Patricia Allen told Axios Denver on Thursday morning.
• Most are probationary employees, she said, and are being cut from multiple divisions, including collections and tax compliance.
• Some employees were laid off early Thursday morning, Allen said. As of mid-morning, more were waiting for an email that was expected to tell them they had 30 minutes to vacate the premises.

"There are many, many, more than 100,000 people working to collect taxes, and not all of them are fully occupied," Kevin Hassett, director of the White House Council of Economic Advisers, told reporters this afternoon.

• Asked if the cuts numbered around 3,500, Hassett said that "probably can get bigger, especially as we improve the IT at the IRS."

What they're saying: "I've been with the IRS for 20 years, and I've never seen this kind of layoff. Never," the union's Allen said.

• The national president of Allen's union, Doreen Greenwald, called the firings a "recipe for economic disaster."
• "In the middle of a tax filing season, when taxpayers expect prompt customer service and smooth processing of their tax returns, the administration has chosen to decimate the whole operation by sending dedicated civil servants to the unemployment lines."
• The White House was not immediately available to comment on the layoffs or their impact on tax season.

Zoom out: Just two weeks ago, IRS employees who are critical to tax season were told they would not be able to take the administration's so-called "deferred resignation" offer until after tax season.

• It's not yet clear whether the layoffs will slow down the filing season, but tax experts are warning about the possibility. The agency has long been plagued by staffing shortages.
• Commerce Secretary Howard Lutnick said Wednesday evening that Trump's goal is to "abolish" the IRS.

Arlene R., who requested partial anonymity for fear of retribution, is a Denver employee who has worked for the past five months in the IRS' special compliance department overseeing collections.

• She was bracing for the termination letter to hit her inbox at any point Thursday morning.
• "So many of us don't even know how we're going to make our rent, how we're going to put food on the table," she told Axios Denver. "This is just absolutely incredible that one man has this power to do this."

Editor's Note: This story has been updated with White House comments.

School leaders across the U.S. are working to reassure parents about potential immigration enforcement on campuses after the Trump administration reversed a long-standing policy discouraging enforcement in "sensitive" areas.

Why it matters: The mere possibility of immigration enforcement on campus could cause widespread fear, leading some students to skip school. This would disrupt their education and threaten school funding, which is often tied to attendance.

Catch up quick: The Trump administration announced on Tuesday that it was ending the policy of avoiding arrests in churches, schools, hospitals, funerals, weddings, and public demonstrations.

• "Criminals will no longer be able to hide in America's schools and churches to avoid arrest," the Department of Homeland Security said in a statement.
• "The Trump Administration will not tie the hands of our brave law enforcement, and instead trusts them to use common sense."

Context: Children in the U.S. have a right to public education regardless of immigration status, meaning schools don't turn back — and in most cases, don't track — whether a student is in the country without authorization.

Zoom in: Some school districts are taking proactive steps to protect students and families, outlining policies that limit cooperation with immigration authorities and reinforce campus safety measures:

• Denver Public Schools, a district with roughly 89,000 students, said on Jan. 14 that principals should deny entry to any government official who arrives without prior appointments or legitimate school business and also initiate "secure perimeter" protocols, locking all exterior doors and halting all entries or exits from school buildings.
• The Salt Lake City School District has urged parents to update emergency contact information and reiterated that it doesn't track students' immigration status and will not report students to immigration authorities.
• The Philadelphia School District said school staff are instructed not to provide Immigration and Customs Enforcement (ICE) officers with any information about students, families or employees, nor will they be allowed in schools without approval from district lawyers.
• Last month, San Diego Unified School District board adopted a resolution saying the district will not assist ICE in the "enforcement of federal civil immigration law" and won't allow access to its facilities or personnel unless officers have a warrant.

Reality check: The districts have long maintained policies that exclude immigration issues from schools; they are mainly reiterating these to alleviate fears among families.

Plus: Some districts in GOP-led states say they'll cooperate with ICE or are staying mum on their plans.

• "Florida schools will cooperate with all law enforcement working to enforce the nation's laws on illegal immigration," Florida's education department spokesperson Sydney Booker told Axios Tampa Bay.
• Northside ISD, San Antonio's largest district, does not plan to issue any communications or FAQs about immigration, district spokesperson Barry Perez tells Axios.

What they're saying: Nicholas Espíritu, deputy legal director at the National Immigration Law Center, says it's not clear what ICE enforcement in or around schools could look like.

• Past administrations have avoided allowing ICE in schools, choosing instead to focus efforts on people with violent criminal histories and who pose a national security threat.
• "One thing is for sure — little children trying to go to school and learn how to read and write don't pose threats to national security," Espíritu says, adding that even the possibility of enforcement could severely disrupt children's education and growth.

Many in the meatpacking industry were happy to see Donald Trump reelected — but are also fearful it won't be able to operate without the workers he may try to deport.

Why it matters: Meatpacking, more than almost any other industry in this country, relies on foreign-born labor, whether documented or not. It would face critical challenges if those workers disappeared due to mass deportations.

• Yet meat-related interests overwhelmingly supported Trump financially in 2024, knowing the potential risks to their business.

The big picture: Meatpacking is dangerous and difficult to staff even in the best circumstances.

• "If you ask anybody on the packing side of things, going back before COVID … no one's going to tell you there's a bigger challenge in the meat supply chain than labor," Ethan Lane, vice president of government affairs for the National Cattlemen's Beef Association, tells Axios.

Zoom in: One oft-cited estimate suggests that 30% to 50% of all laborers in the meatpacking industry are undocumented. Producers will dispute that, but no one disagrees the industry relies on migrant labor.

• "This is a decision by the industry. It's a wink and a nod — this is how they can keep labor costs down," says Debbie Berkowitz, a fellow at the Kalmanovitz Initiative at Georgetown and former OSHA chief of staff.
• Some, like the NC Pork Council, deny that their producers use undocumented labor. But they also concede labor shortages plague the industry, and point to a need for immigration reform to expand visas for laborers.
• The pandemic further exposed how immigrant labor has been used to sustain the industry, with high-profile COVID outbreaks highlighting their vulnerability and the critical role they play.

Zoom out: Trump's team has said their deportation program would (first) target criminals (though an Axios review found that to be a relatively small number.)

• The transition, asked about any plans for undocumented meatpacking workers, reiterated its intent to target "illegal criminals, drug dealers, and human traffickers" in a statement to Axios.

But those who work with undocumented laborers say the mere sight of deportations can have a domino effect.

• "Many of the people in my book, they were or are undocumented, and even if they now have residency … they have family who are undocumented and they're scared," says Alice Driver, whose book "Life and Death of the American Worker" examines the lives of undocumented meatpacking workers.
• Driver and others say the specter of deportations could be enough to tip the industry into crisis, as workers flee or stop showing up to work, even if plants aren't being raided.
• If packing plants are short of labor, that raises another concern: the availability and price of meat.

All-time high prices

Zoom out: Prices for staple meats are already at or near 20-year highs, per the Bureau of Labor Statistics' Consumer Price Index data.

• A pound of fresh, whole chicken that cost $1.36 in Feb. 2020 cost $2.08 last month (+53%), while a pound of 100% ground chuck rose from $4.03 to $5.61 (+39%).
• That's despite most packing and slaughter jobs paying less than $20 an hour, on average, per government data. (The industry says wages are rising, however.)

Context: Trump's tariff plans also threaten to impact crucial export revenue.

• Beef and pork businesses rely on revenue from exports of animal products that aren't part of the American diet but sell well overseas.
• Roy Lee Lindsey, CEO of the NC Pork Council, tells Axios that export value makes up about a third of the price farmers get for hogs today.

Even knowing the threat to their business, the industry got behind Trump.

• Donations to Trump from the livestock industry in the 2024 cycle were nearly double the donations to Kamala Harris, according to OpenSecrets.org data.
• The donors were a broad mix, from large industry trade groups to individual ranches and farms.

Broken communities

Mass deportations also threaten to break up communities that have spent decades building tight-knit bonds through shared workplaces.

• For example: A JBS meatpacking facility in Greeley, Colorado employs about 4% of the town.
• "The problem within the industry is that most packing facilities …. build these types of plants in very conservative, rural communities. I don't know that we're going to have a lot of friends in Weld County," says Kim Cordova, president of UFCW Local 7, representing workers at the plant.

The bottom line: Everyone sees the problem coming, but no one knows what will actually happen.

• "I can't imagine that the meatpacking industry is going to be behind this, behind what Trump does in a business sense," Driver says. "It's going to hit companies hard, it's going to hit consumers hard, because let's find out, who's going to take on that work?"

A handful of top U.S. universities are urging international students who travel home for winter break to be back in the country before President-elect Trump takes office.

The big picture: Trump has vowed to crack down on both illegal and legal immigration, and school leaders are worried one of his first actions could be an executive order limiting entrance to the U.S. like he did with the Muslim Ban in 2017.

Driving the news: At least 10 universities, mostly on the East Coast, have told international students to be back stateside before the Jan. 20 inauguration. They include the University of Southern California, Brown University, University of Pennsylvania, MIT and others.

• USC in an email to students on special visas said they are expected to be in class when the semester starts on Jan. 13, and that this "is especially important given that a new presidential administration will take office on January 20, 2025, and — as is common — may issue one or more Executive Orders impacting travel to the U.S. and visa processing." The school shared the email with Axios.
• "While there's no certainty such orders will be issued, the safest way to avoid any challenges is to be physically present in the U.S. before the Spring semester" begins, the email stated.

Zoom in: Sercan Canbolat, director of Abrahamic Programs and adjunct professor at the University of Connecticut, came to the U.S. from Turkey in 2014 to get his doctorate degree and says that, out of precaution, he didn't travel outside the country during the first Trump term.

• He also says he won't when Trump returns to office in January because he "will take no risk" of not being able to get back in the U.S.
• Canbolat, who has a student visa, says he last visited Turkey in 2021 and wishes he could go back so his family can meet his wife and 6-month-old daughter.
• "It's not easy at all for me, for my family in Turkey. They want to meet her, they want to hold her."

Catch up quick: There are roughly 1.1 million students from other countries studying in the U.S., according to NAFSA: Association of International Educators, a global nonprofit that advocates for international study.

• Those students contribute $43.8 billion to the U.S. economy. They also often pay about triple the amount of tuition that state residents pay.

Reality check: Most universities are not issuing guidance.

• Emory University spokesperson Sylvia Carson said in an email to Axios that the school can't "speculate on anything related to the new administration at this time. Once real policies and mandates have been put into place we can discuss impacts, but it's premature at this stage."
• University of Colorado Boulder spokesperson Nicole Mueksch also said the school can't speculate but that it'll "continue to support" international students "regardless of who's in office."
• Arizona State University, which has the fourth-largest number of international students, is also not issuing guidance, per spokesperson Jerry Gonzalez.

What they're saying: Jill Allen Murray, deputy executive director of public policy at NAFSA, says it makes sense these schools "would try to avoid the risk of even one student experiencing a disruption to their study."

• But "I don't think we're hearing a lot from our members about this particular issue of needing to have students here before inauguration," Murray adds.

Editor's note: This story has been updated with the correct spelling of Sercan Canbolat's last name.