Banff Yoho & Kootenay National Park Avalanche Forecast
Mar 22nd, 2020 5:01PM
New snow, wind and warmer temperatures will elevate the avalanche danger on Monday. Narrow gullies and steep rocky terrain may have small natural avalanches. Step back to more moderate terrain choices until the new snow has a chance to bond.
Snow is expected Sunday night and Monday with total amounts ranging from 10-15 cm depending on the elevation. Winds will increase into the moderate to strong range out of the SW on Monday before dropping down to light again on Tuesday. Freezing levels stay just above valley bottom and some areas could see rain at lower elevations on Monday.
2-5 cm of new snow in eastern areas of the forecast region on Saturday night. Widespread wind effect in the alpine and down into treeline. Sun crusts on solar aspects and buried sun crusts on steep solar aspects. In thin snow pack areas a dense mid-pack sits over a weak faceted base, while deep snowpack areas have a solid base.
Several solar triggered small loose avalanches observed in the past several days and some skier triggered surface sluffing in steep terrain up to size 1.5.
Incoming snow and moderate to strong SW winds Monday will create fresh wind slabs in lee areas at treeline and above. These will be possible to trigger by skiers. Avoid wind loaded areas in steep terrain, especially in thin snowpack areas.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
Deep Persistent Slabs
Use caution in thin snowpack areas averaging 150cm or less. In these areas the basal snowpack layer of depth hoar and facets remains weak, and the mid and upper snowpack is thin enough to allow for triggering of the deep persistent layer.
- Be aware of thin areas that may propogate to deeper instabilites.
- Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.
Valid until: Mar 23rd, 2020 4:00PM