Olympics

A significant rain event creates the potential for naturally triggered large wet avalanches Tuesday night, with gradually decreasing danger on Wednesday. Avoid exposure to all open slopes steeper than 35 degrees, particularly where bedrock slabs may produce glide avalanches. Significant uncertainty dictates conservative travel until we know how the snowpack responds to rainfall.

Several inches of wet snow fell at Hurricane Ridge Monday morning. Since noon on Monday, temperatures have predominantly remained above freezing at Hurricane Ridge. The Ridge has picked up 0.69" of rainfall since Monday evening with rain rates intensifying late Tuesday. Heavy rain should fall Tuesday night with decreasing rainfall ending on Wednesday. With another inch of rain on the way,  we have significant uncertainty regarding how the snowpack will respond, particularly if rain percolates into previously cold, dry layers in the snowpack. A variety of wet snow avalanche problems could develop and each one has the potential to produce large, or perhaps very large, avalanches. Wet slabs may be the most dangerous if water pools on a crust. These avalanches can propagate widely across a slope and sometimes release well below typical avalanche start zones. Wet loose avalanches entrain wet surface snow and grow in size as they accelerate downslope. Glide avalanches can occur on any steep bedrock slab and will release the entire 5 ft deep Hurricane Ridge snowpack. Lastly, cornices are more likely to fail as warm temperatures make them soft and heavy. They can also trigger other types of wet avalanches on the slopes below. Remember, that water percolating through the snowpack may be slow to drain, so even once the rain stops, the threat of natural or human-triggered avalanches remain. If you head out on Wednesday, you will need a conservative mindset and the ability to avoid exposure to all open slopes steeper than 35 degrees. Give the snowpack time to respond to the rapid changes associated with rain and warming.

Hurricane Ridge picked up nearly 3 feet of snow since the start of the year, but was spared relative to the snow-pocalypse that the Cascades experienced 1/5-1/7.  

On Saturday (1/8), NPS rangers and observers noted that S-SW aspects along ridgelines were largely stripped of snow and had a semi-breakable crust.  On northerly aspects and away from wind effect, the storm snow was largely right side up.  Natural cornice fall triggered at least two large wind slab avalanches between Friday afternoon and Saturday afternoon in the Hurricane Ridge area.   On Sunday, ONP Rangers noted several natural loose wet avalanches on steep sunny slopes. 

2021-22 Forecast Schedule: Avalanche danger ratings will be issued for the Olympics every Friday through Sunday and during mid-week holidays. During the week when the Hurricane Ridge road is closed, forecast information will be updated daily to include expected conditions and relevant travel advice under the No Rating label.