1/27/2024 Field Report - Front Range

Rider 1, on a snowboard, and Riders 2 through 4 on skis, met on the morning of January 27 to ski Hagar Mountain. They climbed the southeast face on foot, reaching the summit at about 09:40 AM. They rode from the summit down to about 12,300 feet in elevation. From there, they climbed, on foot, towards the summit again. Rider 1 was breaking trail in front, with the others about 20 feet behind. Rider 1 was on the phone with a friend. Rider 1 took a step up and triggered the avalanche above the group. Rider 1 yelled, "Avalanche," and the friend on the phone asked if it was real. Rider 1 said it was, and the friend called 911 to report the avalanche. The avalanche caught the whole group and swept them about 300 vertical feet down and over a rock outcrop. All four reported being submerged by debris at times, but none were completely buried when the avalanche stopped. 911 contacted the Alpine Rescue Team (ART) about a possible avalanche rescue at 10:33 AM. The group called their friend back at 10:40 AM on Rider 2’s phone to say that they were not buried or seriously injured. The friend facilitated the exchange of phone numbers between Rider 2 and ART. ART stood down from the initial call for an avalanche rescue but met the group in Dry Gulch to assist them out with snowmobiles.

Updated with additional information provided by the group.

Hagar Mountain in Dry Gulch near the Eisenhower-Johnson Tunnels.

The avalanche occurred on the southeast face of Hagar Mountain on an above treeline, rocky, and non-planar slope. It was a hard-slab avalanche unintentionally triggered by a group of backcountry tourers on foot at the time. It was medium-sized relative to the path and produced enough destructive force to bury and destroy a car or break a few trees. The avalanche broke on a layer of facets near the bottom of the snowpack and ran to the ground in place. (HS-AFu-R3-D3-O/G). The avalanche was two to six feet deep, over 1000 feet wide, and ran over 1000 vertical feet.

Storms from mid-October through late December built the bottom of the snowpack. Prolonged dry periods between storms created weak layers in the early-season snow. A large storm cycle from January 4 to January 25 buried the weak, early-season snow. The snow water equivalent (SWE) at the Loveland Basin SNOTEL, 2.75 miles south of the avalanche site, nearly doubled, from 5.0 inches to 9.0 inches. The most intense period of the storm was January 14 to 18, with 1.6 inches of SWE combined with strong to extreme winds from the west and northwest. The storm ended, and January 27 was clear. The weak layers buried by the prolonged January storm cycle led to a Persistent Slab avalanche problem throughout many of Colorado’s mountains. The CAIC documented 117 human and naturally triggered avalanches in the Front Range from January 4 to January 26, with a peak frequency surrounding the Martin Luther King Jr. holiday weekend. Many of these slides broke on the persistent weak layer buried around January 4, and some were triggered remotely or sympathetically. From January 13 to 19, there were 51 avalanches with 27% D2 or larger. From January 20 to January 26, there were 22 avalanches, but 41% were D2 or larger. Of the 22 human and natural avalanches in the Front Range between January 20 and 26, 9 were on east and southeast aspects above treeline, and a significant portion were on slopes like the southeast face of Hagar Mountain.