Avalanche Forecast
Regions: Olympics.
Loose snow avalanches are the name of the game Sunday. Depending on the aspect and time of day, anticipate that you will be able to trigger a small loose avalanche on very steep slopes. Consider the consequences of a small avalanche around terrain traps like gullies and cliff bands before committing to a slope.
Discussion
Snow and Avalanche Discussion
Observations and snowpack tests from the last few days have not identified any problematic layers in the upper or mid-snowpack. Also, no new or recent slab avalanche activity has been reported in the Hurricane Ridge area.
Sunday will be warmer and sunnier than Saturday, so be on the lookout for loose avalanches on all aspects tomorrow that may entrain up to 6" of recent snowfall.
Cornices are normal size for this time of year. There are signs of recent cornice formation. Steer clear of traveling on or below cornices, especially during periods of extended sun breaks.
Forecast schedule
For the 2018-19 winter season, avalanche danger ratings will be issued for the Olympics every Friday through Sunday and during mid-week holidays.
During the week, No Rating will be issued but forecasts will include expected conditions and relevant travel advice. While this avalanche forecast is focused on backcountry avalanche conditions expected in the Hurricane Ridge area, we want to hear about your observations from other parts of the Olympics as well.
Snowpack Discussion
March 4, 2019
Here we are at the beginning of March. The days are noticeably longer, the sun feels warmer, but the winter is far from over. This may be a good time to take stock of Februaryâs events, where we are now, and what we might expect in the future.
A February to Remember
Many longtime Cascade travelers continue to remark about the long span of high-quality travel conditions in February. Indeed, weâve experienced three weeks of very cold and snowy conditions. Backcountry travelers frequently reported, âbest conditions in yearsâ. February also saw a few rounds of natural and human triggered avalanches. These avalanches were different from our more frequent Cascade storm slabs; here today and gone tomorrow. Most avalanches failed on buried weak persistent layers. As such, most zones spent much of February with Persistent or Deep Persistent Slabs in their forecasts.
Natural avalanche in Icicle Creek Feb 13, 2019. Photo: Matt Primomo
With the notable absence of high elevation rain events, snowpacks around the northwest grew remarkably. On the west slope, most weather stations added 2-4 ft of snow depth. East-side locations added 1-2 ft. Mt Hood locations added 4-5 ft. Even with these impressive snowpack growths, many Cascade Snotel sites are recording near or just below average snow depths for the winter. Â
During most of February, snow conditions were soft and powdery making for fun recreating in many areas. Photo Matt Primomo.
Where We Are Now
Lack of avalanche activity on the layer of buried facets from Feb 8 allows us to gain confidence in many areas. In many areas, there has been a lack of avalanche activity and snowpack tests have been less reactive. These two pieces combined have allowed us to drop persistent slabs from some forecasts and shift others to âunlikely.â The exception is the East Cascades where a shallow snowpack has preserved buried facets, and persistent slabs will remain possible until the sensitivity drops further. So, weâre out to the woods, right? Well, maybe. The same cold and stormy weather that brought us excellent snow quality, also allowed us to bury new weak layers. So far we havenât confirmed any avalanches on these shallow weak layers, but they have our attention and weâre tracking them.
Recently our attention shifted to the upper snowpack. Recent avalanche problems have largely focussed on wind transported snow. Several wind events, predominantly from the east, placed wind slabs on a variety of aspect. With the colder than normal temperatures, wind slabs may not heal as quickly as normal.
A small natural wind slab avalanche in the Crystal Mt backcountry. Photo; Dallas Glass
What Might We Expect
As we move into March, itâs anyoneâs guess what specific weather patterns lay in store of us. However, there are two items that stick out in our minds.
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The strength of the March sun: You can already feel it just walking around town. As the sun creeps higher into the sky and the days grow longer, the sun can have a greater impact on the snow surface. When the sun comes out, expect things to change quickly. You may see avalanches conditions change with natural loose avalanches originating from sunny slopes, surface snow becoming thick and heavy, and slabs taking on a moist to wet snow character.Â
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High elevation travel: Frequently March begins to usher in a period where we push higher and deeper into the mountains. Remember, we donât have as much information about these far-flung locations. If you use the longer days of March to travel to bigger objectives, keep your eyes open. When observations donât line-up with the avalanche advisory, you may be experiencing a different snowpack. Itâs times like these we need to stop and reevaluate.
Mt Baker on a nice day in early February. Photo: Lee Lazzara
February was amazing! but March is here⦠thereâs still plenty of winter left. Stay safe out there.
Avalanche Problems
Loose Dry
Loose dry avalanches may run fast and far on very steep northerly aspects while loose wet avalanches may be human triggered or release naturally on steep solar aspects. For loose wet avalanches, pay attention if natural pinwheel or rollerball activity begins and move to different aspects or lower angled slopes.
These avalanche problems are both easy to identify and to avoid. Avoid terrain exposed to gullies, rocks, or trees where the consequences of a small avalanche could be quite large.
Release of dry unconsolidated snow. These avalanches typically occur within layers of soft snow near the surface of the snowpack. Loose Dry avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs. Loose Dry avalanches can trigger slab avalanches that break into deeper snow layers.
Loose Dry avalanches are usually relatively harmless to people. They can be hazardous if you are caught and carried into or over a terrain trap (e.g. gully, rocks, dense timber, cliff, crevasse) or down a long slope. Avoid traveling in or above terrain traps when Loose Dry avalanches are likely.
Loose Dry avalanche with the characteristic point initiation and fan shape.
Loose dry avalanches exist throughout the terrain, release at or below the trigger point, and can run in densely-treed areas. Avoid very steep slopes and terrain traps such as cliffs, gullies, or tree wells.
Aspects: North, North East, North West.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 1