Summer is finally arriving in the coming week, with heat warnings in effect for the interior ranges and west slopes of the Rockies starting this weekend. As a result we can expect mountain hazards related to warming to increase, especially water levels on streams and rivers.
Rumbles of thunder woke me up in Banff early this morning (Thursday), and showery weather is forecast today in all regions (falling as snow at higher elevations, such as at road level at the Columbia Icefields). Unstable weather will continue through Friday in most areas in the Rockies, with clearing beginning to occur that day in the Columbias. Saturday is where the sun and heat kicks in for all areas, but it is only expected to last until mid-week. Models are showing cooling and showers returning by Wednesday, with the exception perhaps being the farthest northern areas.
Although snow continues to linger at lower than normal elevations for this time of year, there has been a significant amount of melt occurring in the last week. It has been looking decidedly more summer-like in the past few days.
That said, you can still expect snow down into treeline on northerly aspects, and gullies and lees of ridges are still holding plenty of snow on south facing slopes as well. Snowpacks on glaciers are relatively deep and unconsolidated.
Difficult travel has been reported due to unconsolidated snow on objectives ranging from alpine climbs to treeline hikes.
Valley bottom hikes and rock climbs are in summer condition in most areas.
Hazards will be closely tied to the temperatures this week. Everything is associated with the amount of snow we still have, and the fact that it will be melting all the way to mountain top. If you are traveling on glaciers or snow you can expect:
- Weak crevasse bridges
- Wet snow avalanches
- Deep persistent slab avalanches
- Cornice falls
- Punchy snow conditions that could cause you to move a lot slower than expected
In addition to all of that, think twice if you need to cross any stream or river: water flows are high and fast right now.
Not everything is doom and gloom though. It looks like we might see some overnight freezes that, combined with clear skies overnight, MAY make snow travel easy and fast for a few hours with middle-of-the-night starts and early-in-the-day finishes. And these freezes also mitigate all the hazards noted above for a short period of time. But as always, making decisions based on the facts presented to you at the time is all important. Plan Bs and having the wherewithal to turn around are de rigueur in case things don't pan out the way the the forecast predicted.
We will be having some beautifully clear and warm weather so choosing objectives suitable to this sort of weather will be your best bet:
- Lower elevation rock climbs; if venturing higher perhaps south aspects will be drier but if there is snow above your route expect things to come falling down from above
- The same goes for hikes. Forest flowers are coming on strong right now. If venturing to treeline be prepared for unconsolidated snow that may shut you down, and watch out for overhead hazard in the form of snow avalanches, cornices, rockfall. There is some mud out there right now too.
- Simple alpine climbs with few crevasses and minimal overhead hazard
- Scrambles on the east slope of the Rockies where snow amounts may be less
I am avoiding:
- Alpine climbs with overhead hazard
- Alpine rock
- Hikes to treeline or above, unless I know the snow travel is consolidated
Enjoy the coming summer weather. With a bit of anticipation and planning there are plenty of safer objectives to choose from.