Accident: Alexander Basin

Observer Name
Bruce Tremper and Brett Kobernik - Accident Investigation
Observation Date
Monday, February 8, 2010
Avalanche Date
Sunday, February 7, 2010
Salt Lake » Mill Creek Canyon » Alexander Basin
Location Name or Route
Slope Angle
Trigger: additional info
Unintentionally Triggered
Avalanche Type
Hard Slab
Weak Layer
Depth Hoar
Accident and Rescue Summary

Accident Investigation by Bruce Tremper and Brett Kobernik - Utah Avalanche Center See the complete photo gallery.

Backcountry skier, Matt Knotts, triggered an avalanche, was caught, hit trees and suffered major injuries. He suffered open, tib-fib breaks on both lower legs and a broken left femur. Since it was obvious that he had suffered major injuries and needed prompt medical attention, is two partners used their cell phone to call for help. Wasatch Backcountry Rescue responded using Life Flight helicopters and quickly evacuated the patient (see the rescue summary).

A group of three backcountry skiers had skied to Wilson Peak, just east of Gobbler's Knob on the Big Cottonwood - Mill Creek ridge line. They planned to ski into Alexander Basin, which is a very steep basin surrounded by large, steep slopes. Since it is difficult to enter from the top, they went down the ridge off Wilson to the north and planned to ski a more gentle slope that the victim and other friends had successfully skied the previous day. They descended a bit too early and found themselves in terrain much steeper and more dangerous than they intended. Everyone felt uncomfortable about the terrain so they tried to traverse to their right to access the slope they planned to ski, but they were stopped by cliffs. They considered putting their skins on and climbing out but they noticed several other ski tracks from previous parties going down into the steep terrain and they thought they could probably make it as well. (The avalanche they triggered took out the pre-existing tracks.)

Matt, the victim, skied last. Clay descended first and John descended an adjacent chute, which came back to join the main chute about a third of the way down. When Matt began descending, he triggered the avalanche. He tried to move to the left in some trees as an island of safety but the slide took him down. He yelled "avalanche" to his two friends below and they quickly turned right and were out of the way of the avalanche and were not caught. Matt was strained through trees and he hit a couple trees very hard, breaking both legs and he came to rest in a group of trees on a small island at the side of the chute, where he was wrapped around a tree.

John and Clay helped stabilize him and quickly realized that he needed prompt medical attention with two open tip-fib fractures and a femur fracture. They had some difficulty using their cell phones as the reception was not very good. They tried calling Alta Central without success and they then called 911. John helped keep the victim warm by bear-hugging him and trying to keep him calm amid the great pain of his injuries. Air Med arrived and assessed that they would need professional avalanche help, so they picked up Brandon Dodge and another Brighton patroller (members of Wasatch Backcountry Rescue - a consortium of ski area avalanche professionals). They landed on the debris and WBR members and medical personnel hiked 400 vertical feet up a very steep slope to access the victim, who was caught in trees on the flank of the slide. They stabilized the patient with fluids and pain meds and lowered the patient in a liter using rope lowerings to the debris below where he could be loaded into a helicopter. Their prompt and expert response, no doubt, saved Matt's life and they were the real heros in this accident.

Rescue summary from Brandon Dodge who was part of the evacuation:

Salt Lake County SAR was activated at 1430 hrs for a backcountry skier injured in an avalanche. An Airmed helicopter was dispatched to locate and assess the scene. The Airmed crew located victims and decided to bring in outside snow safety personnel to assess avalanche hazard. A combination WBR, SAR, Airmed and Brighton Snow Safety team was flown to the scene and determined a hot landing zone was appropriate. Victim was hung-up about 500ft above deposition zone in large trees lining the side of the chute. A four person rescue crew ascended to victim. Victim was treated for severe injuries to both legs, stabilized, packaged and rope lowered 500 ft to Airmed helicopter.


See the


An overview of the area.

A close look reveals the gentler chute on the looker's left they intended to ski. Instead, they descended the chute on the looker's left of the fracture, where they triggered the avalanche. The initial avalanche sympathetically triggered the two other chutes on the right, making a much larger avalanche. The victim was stopped in an island of trees at mid slope.


After they realized they were in the wrong place and felt uncomfortable about the steepness and seriousness of the terrain. They talked about putting on their skins and climbing back up and out, but saw all the other tracks from previous skiers who had descended successfully, so they decided to go for it. The avalanche took out all the tracks from previous skiers. Luckily after Matt yelled "avalanche", Clay and John got off to the side and were not caught. Matt, unfortunately, was caught and impacted a couple trees at high speed and lodged in an island of trees.


A flank fracture where Brett is examining the weak layer. This shows the deepest section, which was about 3 feet deep, but most of the fracture was around 1.5 feet deep.