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Archived

Avalanche Forecast

Apr 19th, 2018–Apr 20th, 2018
Alpine
1: Low
The avalanche danger rating in the alpine will be low
Treeline
1: Low
The avalanche danger rating at treeline will be low
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Olympics.

Even with low avalanche danger, hazards still exist in the mountains Friday. Continue to look for signs of unstable snow and other springtime issues. Use travel routes and techniques that minimize your exposure to overhead hazard and high consequence terrain such as above cliffs and gullies.

Detailed Forecast

Expect a solid overnight refreeze, cool temperatures, and mostly cloudy skies to limit the development of avalanche problems Friday in the Olympics. Snow surfaces will be firm to start the day. Be careful if you are traveling on steep slippery surfaces where it may be difficult to stop a fall.

Daytime warming and morning sun breaks should allow for some softening of the snow surface. Look for signs of wet surface snow developing as you travel. New rollerballs, fresh fan shaped avalanche debris, and wet surface snow deeper than your ankle, all indicate that the potential for loose wet avalanches has developed on similar steep slopes. If you experience these conditions, take time to evaluate your terrain choices. Could a small loose wet avalanche carry me into terrain where I may be injured or killed? Would another route be safer?

Afternoon clouds and snow showers will slow the development of avalanche hazard.  

Several other springtime hazards exist in the mountains. Cornices have grown large in many areas all winter long. Glide cracks have formed on some smooth, steep slopes. Creeks are opening and flowing high and fast. Use extra caution and limit your exposure if you choose to travel near or below any of these potential hazards.

Snowpack Discussion

Warm temperatures and sunshine Thursday likely created a melt-freeze crust on most slopes in the Olympics. This should only increase the thickness of the crust formed from rain showers earlier in the week.

The most recent significant snowfall occurred last Friday (4/13) through Monday (4/16), depositing 10-16 inches (25-40cm) of snow in the Hurricane Ridge area. Generally mild weather over the last several weeks has allowed the upper snowpack to gain strength. While several layers can be found within the snowpack, there are no significant layers of concern at this time.

Observations

No recent observations. 

Avalanche Problems

Loose Wet

Release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. They generally move slowly, but can contain enough mass to cause significant damage to trees, cars or buildings. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

 

Travel when the snow surface is colder and stronger. Plan your trips to avoid crossing on or under very steep slopes in the afternoon. Move to colder, shadier slopes once the snow surface turns slushly. Avoid steep, sunlit slopes above terrain traps, cliffs areas and long sustained steep pitches.

 

Several loose wet avalanches, and lots of pinwheels and roller balls.

Loose wet avalanches occur where water is running through the snowpack, and release at or below the trigger point. Avoid terrain traps such as cliffs, gullies, or tree wells. Exit avalanche terrain when you see pinwheels, roller balls, a slushy surface, or during rain-on-snow events.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Unlikely

Expected Size: 1 - 1