Little Cottonwood's avalanche towers: what changed, and what the records don't yet show

In summer 2024, the Utah Department of Transportation installed 16 Wyssen avalanche towers on the Mount Superior ridgeline above Little Cottonwood Canyon Road, SR-210, and tested them in early December. Triggered by wireless signal, the towers deploy explosive charges that hang just above the ground to start avalanches. ^[1][2]

UDOT's innovation catalog lists the project as fully implemented on Aug. 31, 2024. The results it names are operational: control avalanches triggered without artillery, which it says carries risks when fired over populated areas like Alta; less noise and wildlife disturbance; more precise targeting; and no unexploded rounds left on the mountain. It gives no figures for closure hours saved. ^[3]

Why the towers

Before the towers, avalanche and road crews used howitzers to trigger about 330 controlled avalanches each season, UDOT said when it announced the project in July 2024. Steven Clark, UDOT's avalanche safety program manager, called it part of a long-term plan to reduce the military artillery fired in the canyon. ^[2]

At a November 2023 Alta Town Council meeting, Clark put the estimated cost at more than $6 million, partly federally funded, according to the draft minutes. That was an estimate before construction, not a final cost. ^[4]

The towers joined an existing program. A February 2024 Transportation Commission tour summary said UDOT's Region Two used 10 full-time avalanche forecasters and 52 part-time seasonal workers, with five 105 mm howitzers and 38 remote avalanche control systems. ^[5]

A caution from UDOT

At Alta's Nov. 13, 2024, council meeting, Clark said the goal was to reduce road closures but cautioned that the frequency of closures might not change significantly in the short term, according to the minutes. He also cited worker and public safety, research on health risks from artillery blasts, and replacing outdated equipment. ^[6]

That means a winter with many closures would not by itself show the towers failed, and a winter with few would not prove they worked.

What a closure involves

Little Cottonwood has 64 slide paths, and more than half of SR-210 is threatened by avalanches, according to UDOT. The road is fully closed to the public while avalanche control is underway. Mount Superior covers only part of that exposure. ^[7]

Control work cannot happen with people near the targets, so backcountry areas close first, typically at 10 p.m. the night before a planned road closure. UDOT still uses both remote systems and artillery. ^[7][8]

For a baseline, UDOT's 2022 environmental impact statement for the canyon reported that from 1999 to 2018, SR-210 closed for part of the day for avalanche control an average of 10.8 days a year, for an average of 56.3 hours a year. Those are older averages, not a measure from just before the towers went in. ^[9]

Winters don't hold still

Weather makes before-and-after comparisons hard. In April 2023, during what it called a historic winter, UDOT said it had closed the two Cottonwood canyons more than 30 times. ^[10]

The first winter with the towers, 2024-25, brought the Central Wasatch a fragile snowpack with persistent weak layers stressed by a series of small storms, according to the Utah Avalanche Center. In 2025-26, the center described a warm season with a long midwinter dry spell, ended by a storm cycle beginning Feb. 17 that brought up to 50 inches of heavy snow. ^[11][12]

Those reports describe the backcountry snowpack, not UDOT's road operations.

What would show the effect

A fair test would need UDOT's closure logs by canyon and road segment, with start and end times and reasons, plus records of when the towers were used, how long debris took to clear, and storm conditions, across several winters. None of the records reviewed for this story join those together.