We (party of 3) ice climbed in Santaquin Canyon today looking to do Backoff and/or Squash Head. We opted for Backoff first and arrived at the base around 11:15am. We climbed and top roped the route.

At approximately 12:45pm while on Backoff we heard a rumbling noise from an undetermined direction. As the sound became louder, we could tell it was an avalanche and it seemed to come from the gully to the north, which is the route called Squash Head. We quickly wrapped up our session with the concern that Backoff also has similar terrain above it and perhaps another slide could happen on top of us.

After getting back to the road we could indeed see that a slide occurred on Squash Head. The debris pile covered all of the staging area, spilled both down the approach gully and also into the trees off of the staging area. The debris was dirty snow. Logs larger than 18” in diameter and 15’ long were in the debris. The size of the debris appeared it might have been able to burry a person, particularly had they been knocked over by the heavy wet debris. This slide would have been extremely dangerous to a party on route. One of our party surveyed the staging area while we spotted from the trees to climber’s left. He did not notice any signs of other climbers.

One of our party had been in Santaquin last season (2019-02-02) near these routes when a series of avalanches occurred. Observations from that incident are logged on the UAC site. Last night I reviewed those observations as well as the forecasts for the days leading up to the slides last year. My interest in reviewing the previous incident was to determine what the conditions were so that we did not end up in the same situation. I did not feel that the conditions last year were the similar enough to those today to cause us to change plans.

Today’s forecast was predicted to be warm (+45F), and the forecast was accurate to what we felt. This is very warm for ice climbing, particularly when the route(s) are in known avalanche terrain. Our rationale for proceeding with our day was that the incident in Feb. 2019 occurred for very different reasons than the conditions we experienced today. See those reports for more detail.

The weather has been stable for many days prior to today—clear, warm, and moderate wind, but little available snow to transport. The conditions today did cloud up on our walk in. My hypothesis is that the snow has been very stable in previous days despite the warmth and sun. Today the weather was slightly different, warm but cloudy. This could have warmed north facing snow more than previous days because it was not a clear sky. The cooler snow on these aspects may have naturally released because of warming from the cloudy sky today. Another possibility might be a glide avalanche since there are many slabs of rock above the route. From the ground it was impossible to see the starting zone and therefore any more information about the cause.