Avalanche Forecast

Warm front moisture should begin moving into the Northwest on Tuesday especially to the Olympics and north to central Cascades. The avalanche danger levels will be a moving target as they rise on Tuesday especially in the Olympics and north to central Cascades.

SW alpine winds are likely to begin to build new wind slab on mainly N-SE slopes on Tuesday. Alpine winds have been predominately from the SSE at Hurricane the past few days. Hence W to SE slopes will be indicated. But watch for firmer wind transported snow that indicates wind slab on all aspects in areas of more complex terrain.

New storm slab is likely in areas that rapidly accumulate more than a few inches of new snow. The warming trend will also help build upside down denser snow over initial lower density snow.

Recent cornices are very large. Make sure to avoid areas on ridges where there may be an overhanging cornice as well as travel on steep slopes below cornices! Natural cornice releases and resulting slab avalanches are unpredictable. See a blog post regarding cornices here.

Loose wet avalanches will not be listed as an avalanche problem but will be possible in the below treeline where there is significant rain and warming. Watch for wet surface snow deeper than a few inches, pinwheels or initial but growing natural releases.

You will need to keep a sharper than usual eye on weather conditions if you take a trip into the backcountry on Tuesday. Be prepared to ratchet back your plans if winds become stronger and snow or rain becomes heavier than you expect and you see signs of instability such as cracking of new snow layers or loose wet avalanches before Tuesday night.

The avalanche danger should continue to significantly increase on Tuesday night.

Weather and Snowpack 

The first week of March was very cool and snowy. This was followed by periods of heavy rain in the second week of March. This caused significant avalanche cycles in most areas March 9-10. Significant snowpack consolidation occurred over this period due to rainfall and warmer temperatures. 

Another strong low pressure system brought several inches of rain to the west slopes of the Olympics and Cascades on Friday, 3/17 through early Saturday morning 3/18. Rapid cooling later Saturday morning was followed by generally light snow showers with little in the way of new snow accumulation. The rain event 3/18-19 has formed a very strong crust layer, now buried by this past weeks storm snow.

Since Wednesday, daily weather systems crossed the Northwest. In the Hurricane Ridge area, about 2 feet of snow has fallen over the past five days as of Monday morning.

Similar to most of the recent wind patterns, the latest front passing the area Sunday had moderate sustained S-SE winds. This has transported available snow to build fresh wind slabs in the Hurricane Ridge area.

Daily early spring warming temperatures has allowed surface snow melt and consolidation, at nearly the same rate as accumulations. With about 2 feet of snowfall received in the past five days, the total snowdepth has increased only about 10 inches. 

Recent Observations

NWAC pro-observer, Matt Schonwald was in the Hurricane Ridge area Thursday afternoon. Moderate S-SE winds were quickly building fresh 10-12" wind slab on lee aspects and scouring windward aspects to the most recent rain crust. Wind slabs near treeline were becoming increasingly sensitive by the end of the day. The new cornice formation was occurring along ridgelines. 

Matt was back in the Hurricane Ridge area on Friday. Hurricane Ridge continues to live up to its name because the wind was again the main story with fresh wind slab becoming deeper and more sensitive on lee slopes which included some W slopes near treeline. Fresh and large cornices were also building and deemed likely to fail. All wind loaded avalanche terrain was avoided. Generally shallow, loose wet avalanches occurred below treeline on solar aspects until the cloud cover increased late morning.