Turnagain Pass Avalanche Forecast

No new avalanches were seen or reported yesterday. However, there was relatively little backcountry traffic and poor visibility. The last know avalanches were on Sunday and Monday when people found reactive storm slabs within the new snow (~10-14″ at Turnagain). The sun also induced some storm slabs on Monday afternoon due to warming.

Example of one of the smallish storm slabs triggered on Monday. This was on Tincan. Photo by Mike Records 4.10.23.

Snowfall overnight and this morning has added another 3-6″ of new snow, possibly more in favor areas like Portage and Placer Valleys. Turnagain Pass may have only received 1-2″. The snow has come in with relatively light easterly winds along the ridgetops and is making its way to sea level. Light snow showers may continue until around noon with little additional accumulation.

The avalanche problem ‘icon’ above may say storm slab, but really there are all kinds of avalanche problems to be on the lookout for. The most concerning will be higher elevations that saw wind loading yesterday. Wind slabs up to 2′ deep formed by yesterday’s bump in easterly winds, gusting in the 30’smph, could be found and triggered by us. These could be obscured by the light snow from overnight. There could also be some storm slabs lingering in areas out of the winds that are sitting on a crust from early April. Loose snow sluffs will probably be easy for us to trigger on steep slopes and cornices could be teetering close to failure. It is a day to really pay attention to the surface conditions and the Red Flags (recent avalanches, cracking in the snow around us and collapsing/whumpfing in the snow under us.

Daytime warming and avalanches possible in the afternoon:  This afternoon if the clouds break and the sun peaks through, we could see some naturally triggered avalanches in the storm snow from last night as well as that from over the weekend. Look for loose snow sluffs and shallow slabs as the surface snow heats up later today. These could be triggered by us, or naturally. As is often the case, a smallish sluff can trigger a slab making for a larger avalanche.

Snowpack in the Placer Valley area. More snow fell here than at Turnagain. The storm snow in the lower elevations is stabilizing, but much more uncertainly exists in the higher elevations. 4.12.23.

Example of the surface snow heating up and becoming sticky – and what we call ‘slabby’. This is a red flag for creating larger sluffs and slabs in steep terrain due to warming of otherwise loose and dry storm snow. 4.11.23.

In addition to the concerns related to the new snow mentioned above, we still want people to remember there is a small likelihood of triggering a very big avalanche. This would be on weak snow that was buried in mid March and is 3-6′ deep. It has now been over two weeks since we last saw the last deep slab avalanche. We have been tracking the weak layer in snowpits for nearly a month, and although it is showing signs of gaining strength we don’t totally trust it. To avoid the problem, limiting traveling on or below steep slopes. As time goes on this type of avalanche is becoming less and less likely, but we shouldn’t forget about it yet.