Bollettino valanghe

Stevens Pass

Jan 15 – 16, 2019
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Archiviato · scaduto 8 years ago

Pericolo valanghe

Wed
Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
Apri la mappa completa

In sintesi

The Bottom Line: While Low Danger doesn't mean no danger, Tuesday will be one of the less avalanche prone days of the season, so far. If you see rollerballs or find wet snow on the surface of sunny slopes, it’s time to start avoiding similar slopes. Loose wet avalanches can be dangerous if they push you into trees, rocks, or off of cliffs.

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1
    The concern for loose wet avalanches is being maintained by warm temperatures Monday night and sun in the first half of Tuesday. You could still encounter them on steep slopes that face the sun. On Tuesday, southeasterly aspects may be the most avalanche prone. Slopes on the west side of the pass may also be of concern, where temperatures are substantially warmer. Otherwise, loose wet avalanches have mostly run their course. A project a cooling trend and building clouds should limit avalanches by the afternoon.

    If you see roller balls, notice the surface crust is melting and becoming wet and heavy, or see small loose slides that begin entraining snow on any aspect, use caution on steep slopes and near terrain traps. You can find these avalanches around gullies, cliffs, and rocky slopes. These features can increase the consequences of an avalanche.

Regional Synopsis

January 10, 2019

We’re about a month into our avalanche forecasting season, and what a wild month it has been. We’ve seen the snowpack grow from near non-existent to over a 100 inches deep at Mt Baker. We’ve seen avalanche warnings blanket our coverage area, had several widespread large natural avalanche cycles, and seen persistent weak layers plague nearly every zone. While the active weather pattern has been a welcomed sight, it’s hard to catch your breath.

It looks like this weekend, and extending into next week, we are entering a calm period in the weather. High pressure over Idaho and Montana will keep Pacific storms at bay for at least the short term. As we enter this period of nice weather, there are a few things on our mind here at the avalanche center.

Old Persistent Weak Layers
A high elevation rain event on January 3rd did us a favor in many locations. Besides heavily stressing old weaklayers, the rain created a very strong met-freeze crust, making it extremely difficult to trigger deep avalanches.

There are a few exceptions, and they can be found mainly in the eastern forecast zones. The East-North zone around the Methow Valley and WA Pass did not experience significant rain above 5500 ft, potentially leaving some older weak layers in tact. Areas further east including, but not limited to, Icicle Creek and the Wenatchee Mountains did not receive enough rain to form a strong thick crust. In all of these area, older persistent weak layers are still suspect.

An avalanche on a persistent weak layer in the East-Central zone. Photo: Matt Primomo


Higher Elevations and Remote Trailheads
Stormy weather over the last month has been keeping most of us closer to common trailheads and recreating at near and below treeline. With nice weather on tap, some of you may be thinking about heading into higher elevation terrain and exploring around more remote trailheads. If you are heading out, take time to consider a few key pieces of information.

  • At higher elevations the snowpack is very deep and wintery. This stands in stark contrast to the lack of snow at lower elevations. The snowpack you’ve seen on previous outings this winter, doesn’t represent what you will encounter at higher elevations.

  • We have not received much information about the above treeline nor remote location snowpacks. That means we have a high degree of uncertainty in these areas.

  • You will need to make observations as you travel to confirm if the avalanche forecast is applicable the the area where you are traveling. When observations lineup with the information in a forecast, its valid. If you see observations that don’t lineup, it’s time to take a step-back.

  • If you are heading into our regions highest alpine terrain, remember, NWAC forecast apply to areas below the main Cascade crest, or about 8000 ft. So, if you plan to travel to higher elevations on Mt Baker, Mt Shuksan, Mt Rainier, Mt Hood, or similar areas, you will need the skills and information to evaluate the terrain and snowpack.

If you’re heading into higher elevation terrain, remember we don’t have much information about these snowpacks, and therefore have a higher degree of uncertainty. Photo: Simon Trautman

We’d like to thank our NWAC Community for all the wonderful public observation this year. If you are heading out into the mountains, we appreciate you taking the time to let us know what you saw. This is a great way to contribute to the creation of your avalanche forecast. You can submit observations here.

Enjoy the sunshine!

Regioni coperte