Observation Date
2/21/2019
Observer Name
Garcia/Matthews
Region
Moab
Location Name or Route
Trans La Sal
Weather
Sky
Obscured
Precipitation
Light Snowfall
Wind Direction
South
Wind Speed
Moderate
Weather Comments
Another cold, windy, snowy day in the La Sals. Moderate winds out of the south were moving a lot of snow around today. Light snowfall all day long. The sun would poke through the clouds every now and then.
Snow Characteristics
New Snow Depth
4"
New Snow Density
Low
Snow Surface Conditions
Powder
Snow Characteristics Comments
Another four inches over night. Light and Deep. Turning conditions are 5 star right now.
Red Flags
Red Flags
Wind Loading
Cracking
Collapsing
Poor Snowpack Structure
Red Flags Comments
Winds continue to blow in the moderate range out of the south. A lot of snow was moving around today. We had occasional shooting cracks in the new snow today as we traveled across W, NW, and N facing terrain. A very steep North facing slope adjacent to where we skied collapsed and spider webbed, but did not avalanche. Poor snowpack structure remains. We found very weak snow in shallow areas that have been subjected to wind scouring the past couple weeks. These areas have well developed facets on the ground with the new storm snow sitting on top. It has been really cold all week, and the wind scouring has accelerated the process of temperature gradient metamorphism in these shallow areas.
Avalanche Problem #1
Problem
New Snow
Trend
Same
Problem #1 Comments
In our travels today the surface snow varied from uncohesive light density snow to more cohesive and slab like depending on aspect and elevation. A couple hand shears fell apart, and some pulled out nice cohesive blocks. In some spots the surface snow would crack out around our skis. We had occasional shooting cracks, especially in any wind deposited areas. We did not encounter any sluffing in the new snow. The new snow cracked and collapsed on a steep North facing slope adjacent to where we skied. (Photos below). New snow avalanches will be a concern tomorrow as well, especially if we get the forecasted amounts of snow.
Avalanche Problem #2
Problem
Wind Drifted Snow
Trend
Increasing Danger
Problem #2 Comments
Light winds down low were moving snow all day. On the ridge tops winds were moderate and rapidly loading lee slopes. We watched North facing slopes get loaded all day long. While ascending West facing slopes we encountered scouring and loading patterns on subtle terrain features. Small ridges were almost completely scoured while adjacent slopes only 100 feet over were deep and loaded. These drifts were fresh and would crack at our feet as we moved across them.
Some photos of the shallow wind scoured zones where we encountered very weak faceted snow beneath the new snow. In the second photo you can make out the facets on the underside of a crust. Deep Trail Breaking. Shooting cracks.
In these two photos (Courtesy of Tim Matthews) you can make out where the steep North facing slope collapsed and cracked out, but did not avalanche. We were skiing on a connected slope, and the collapse is most likely due to our weight on the slope.
Considerable danger today. With more snow and wind on the way tomorrow will be another day of considerable, possibly rising to high if we receive a lot of snow.
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable
