Avalanche Forecast

Cooler, with a mix of sun, clouds and snow flurries for the next few days as a high pressure shifts to the east and the next low pressure moves in Sunday.  

Thursday Night: Mostly cloudy with broken clear skies, light and variable wind, freezing level 600m. Alpine Low -6C.

Friday: Cloudy with scattered flurries, light and variable winds, freezing level 800 m. Alpine Low -10C / High -6C

Saturday: A mix of sun and clouds with isolated flurries, light to moderate westerly winds, freezing level 700 m. Alpine Low -10C / High -7C

Sunday: Cloudy with snow flurries, Accumulations 1-8cm (more snow to the south), light-moderate Southwesterly winds, freezing level 700 m. Alpine Low -10C / High -7C

Avalanche hazard remains quite variable and dependent on snowfall amounts, freezing rain intensity and freezing lines experienced during this recent storm. Certain regions received 40cm of snow while others barely saw 10cm. Most areas experienced high freezing levels, snow, then rain, then more snow. As conditions cooled, avalanche activity tapered. Lower hazard exists in areas with less overall snow fall and thicker rain crusts.  

Numerous reports from Wednesday have come in describing the poor bond of new snow to the recent rain crusts producing small to large avalanches 5-25cm deep. Skier controlled small avalanches are being reported in addition to explosive control small and large avalanches at tree line and in the Alpine.  

On Tuesday, at the peak of the cycle, reports of large avalanches (Size 2) naturally and from skier controlled and explosive control work on Tuesday. A few Very Large (Size 3) Natural avalanches were reported running to valley bottom along the highway corridor.  

Our eyes and ears in the mountains are limited this winter due to fewer professional observations. If you go out in the mountains, please share your observations on the Mountain Information Network (MIN). Photos are especially helpful! Thank you so much for all the great MINs submitted so far!

The combination of heavy snow and rains with the warm storm earlier this week followed by cooler temperatures has reworked the snowpack. Anticipate refrozen surfaces below treeline up to 1800m or "dust on crust". 5-20cm of recent snow (higher levels to the far south) sits atop the highest crust and is bonding poorly. 

In many areas, freezing rain in the middle of the recent storm has created a thick rain crust which thins with elevation up to 2300m. In some areas there are two rain crusts: a thin crust near the base of the recent storm snow and a second thicker (1-5cm) crust near the surface. See this MIN report from near Kokanee Glacier & this MIN report from the South Columbia near Hall Mountain. This MIN from backcountry near RMR reports a crust up to 2250m.

We know that prior to this storm there was a widespread large surface hoar. We know that heavy rains have made this layer no longer an issue in many areas. However, we suspect this layer may still be preserved in many tree line locations which were not as affected by high freezing levels and rain events. In other words, if there is no THICK rain crust at and below tree line, be on the look out for buried surface hoar.  

In the Alpine, recent winds will have redistributed snow. These storm slabs sit atop suncrust on solar aspects.  

The most notable layer in the lower snowpack is from early November rains (Nov 5 Crust), which is now sitting near the base of the snowpack and is likely surrounded by a weak layer of sugary facets. It is most likely to be reactive to human triggers on shallow rocky slopes in the alpine.

• Investigate the bond of the recent snow before committing to your line.
• Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
• Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
• In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.