Canadian Rockies Weather is known for being unpredictable, extremely violent, and highly variable. Over the course of a week, it is not uncommon to see a windless 5°C with sunshine. A day later will bring 100km/h winds, massive snowfall, and -30°C temperatures. These conditions do vary throughout the season, so it is good to get an understanding of what the seasonal trends are and how they can affect the snowpack.
Weather is also highly geographically dependent across the range, with storms sometimes only passing through certain areas.
One unique factor affecting the Rockies is that weather runs perpendicular to the mountain range typically. Contrast this to the Alps in Switzerland or other ranges that are parallel to weather. This is important because it means that particular in the summer, weather can “stack up” on the west side of the range. This can result in huge dumps of snow and high winds that tend to come in short, but severe storms.
There are a number of valuable weather resources for planning your ski touring mission in the Canadian Rockies. Be sure to take these forecasts with a grain of salt when planning your backcountry skiing trip. It is important to understand the larger cycles in weather patterns and how they change throughout the season. Use your experience and judgment and make good, conservative decisions before travelling into the backcountry.
Early Season Canadian Rockies Weather
October – December
The early season can be a mixed bag, highly dependent on global weather conditions such as the position of the Jet Stream and Polar Vortex.
In good years, the season starts strong with steady dumps of snow and moderate temperatures throughout October and November. This can result in a nice stable snowpack and good coverage early in the season
During these seasons, it is often also possible to access and ski larger couloirs and other high consequence features. There is often a lack of overhead hazards like cornices. Cooler temperatures overall prevent afternoon warming from becoming a factor. When temperatures stay moderate without any major swings, avalanche danger can remain low for a long time as well making for an excellent early ski touring season.
Alternately, in bad years a trend of extreme cold and/or hot temperatures will delay snow coverage until later in November or December. Early cold snaps and a lack of precipitation are ideal for ice climbers. However, they create significant access issues for skiers due to the lack of coverage at lower elevations.
Even if there is good early season coverage, a long period of extreme cold will create a highly faceted snowpack for most of the early season. This means that ascents can quickly become extremely arduous, with upwards progress becoming impossible due to waist-deep sugar snow.
In most cases, these deep facets will then become a serious, often season-long hazard. They will continue to exist as deep persistent weaknesses, continually buried by denser snow during the mid-season and sometimes resulting in massive failures, particularly later in the season.
Regionally, Kananaskis often has a very poor early season due to a lack of snow. Banff, Kootenay and Lake Louise can be a little better. Icefields Parkway and Yoho are typically the best, thanks to their high altitude.
Mid-Season Canadian Rockies Weather
January – Early March
Midseason weather can remain somewhat fickle. However most seasons it is often more predictable overall than the early season. The mid-season will usually see less variable temperatures as a rule (usually ranging from -20°C to 0°C). Also common are fairly consistent storm cycle bringing fresh snow on a regular basis. While this stability usually means the snowpack is more predictable, it is very important to be aware of deep persistent layers that often exist from the early season, and how wind events and storm cycles will have an impact on these often fragile inter-layer relationships.
One of the best parts of the mid-season in the Rockies is that coverage becomes extremely good at this point. Stable weather combined with lower sun angles means solar warming isn’t too much of an issue most of the time.
Big days, big elevation and big snow is the theme. Nailing a bluebird day after a huge storm with no wind is an incredibly memorable experience.
However, there are almost always a number of serious accidents in February-March. Many start to pursue large objectives in the face of incoming storms, or pushing it too far into the alpine when winds have created dangerous slabs.
While the weather can be very good, it can also be very bad. Huge storms bring in high winds, massive snowfall, and zero visibility in the alpine. It is a common occurrence to be completely socked in on a high snowfield or glacier, despite a previously favorable forecast.
March – Early April
Canadian Rockies weather transition season can be a very mixed bag weather-wise. Objective hazards begin to become significant issues. Cornices are often fully formed, and daytime warming starts to become a factor. On the flip side, there can be cold snaps that will quickly rot out the bottom layers. A big storm or hot temperatures will create an overload situation rapidly. Sometimes only in a period of a few hours.
The biggest hazard in this time of year is definitely the transition to periods of hot weather. Rapid daytime warming can become a significant looming risk as longer days and higher sun angles become the norm.
It is very important to check the forecast when heading out. This preparation is critical to understand what the risk of warming may be. A cold -10°C morning with overcast clouds can quickly morph into blue skies, significant solar effect, and positive temperatures.
There have been many many deaths in the Rockies and other nearby ranges. Parties failed to predict the speed of warming resulting in catastrophic avalanches as high alpine faces let loose.
An early start is CRITICAL to safety in the Candian Rockies during this time period. Remaining observant is also important, as predictions can be wrong and sometimes temperatures will rise faster than expected.
Despite these dangers, the transition season can offer some of the best snow and conditions throughout the whole season. Full snow coverage is typical here. Longer days mean it is possible to start pursuing bigger objectives. A long period of stable temperatures can have either a positive effect or a negative effect on deeply buried persistent weak layers. In some cases, warmer temperatures and increased humidity will “heal” the pack, and result in bomber, solid conditions throughout.
In some cases, however, low humidity and cooler temps can mean those deep persistent weaknesses will remain until the end of the season. These sleeping giants are ready to release catastrophic avalanche cycles once the spring warming pattern begins. These years require a heightened level of caution as it can be very difficult to know where they remain.
It is worth pursuing northern aspects in this time period to find sheltered snow and cooler temperatures throughout the day. Be aware of any overhead hazard that may be subject to more solar warming than where you are skiing.
Late Season Weather
April – June
For many people, April is when skiing begins in the Rockies. Highly predictable high altitude Canadian Rockies weather cycles and warming patterns mean early starts and early finishes. Typically, there has been a major avalanche cycle by late April. This can erase the deeply buried persistent layers across the whole range some seasons.
Many years will also see late storm cycles bringing massive dumps of dense, moist snow. Thise creates a short avalanche cycle, and then days of blower, bottomless powder. Snow remaining particularly good on sheltered northern aspects.
Solar warming is a major factor, as with transition season. However, most aspects will only see wet sluffs in the afternoon. These can be avoided with careful planning and aspect management.
That said, the snowpack can be incredibly predictable along with the predictable temperatures. Early morning starts will often mean climbing styrofoam, supportive snow to the top with perfect corn snow descents. Returning to the valley before daytime warming turns the snow isothermic is key.
A good Canadian Rockies weather forecast can also open the door for big traverses in places like the Columbia and Wapta icefields. Whiteouts can be dangerous, but high altitudes and blue skies are prime traverse conditions.