Understanding the climate of a region will provide insight into the range of avalanche conditions that should be anticipated. This is particularly important when evaluating and mapping avalanche potential. Climate records often provide information on the frequency, timing, and magnitude of future avalanches. In addition, estimates of averages and maximums of snowpack depth can provide information on how often snowpack depth thresholds for avalanche triggering are exceeded.
The primary source is through the National Climate Data and Information Archive at Environment Canada (http://climate.weather.gc.ca/index_e.html). This database provides specific records, as well as daily, monthly, and yearly climate averages and extremes for many locations across Canada. There are several different online products available on the website:
Climate Data Online. Provides direct access to historical weather records for specific locations and dates. Hourly records are available, as well as daily and monthly means. Temperature, precipitation, wind, and snowpack heights are available.
Almanac Data. Provides average and extreme temperature and precipitation values for a particular station for a given day of the year.
Climate Normals and Averages. Provides climate averages and extremes for specific locations over 15+ year periods. Also, a record set containing daily precipitation, temperature, and snow-on-the ground values are available for download from the Canadian Daily Climate Data (CDCD) link.
Automated Snow Pillow Data (ASP). ASP stations measure SWE on the ground, and then relay that data via GOES satellite every one to three hours. Current SWEs are plotted with the previous year’s data, as well as the maximum, minimum, and mean values. Other data available include hourly temperatures, cumulative precipitation, and snow depth.
Manual Snow Survey Records. Conducted up to eight times per year at the beginning of every month from January to June, with extra measurements mid-month in May and June. Records include snowpack depth, and SWE data.
The BC Ministry of Transportation and Infrastructure (MoTI). MotI maintain two principle weather station networks in BC: the Remote Avalanche Weather Station (RAWS) network, and the Road Weather Station (RWS) network. RAWS are located in inaccessible locations, and are highly valuable for avalanche forecasters since they provide weather information from high elevation mountainous environments. RWS stations are exclusively road-elevation sites, but may also provide valuable weather information. Historical RAWS and RWS data more than one month old are available from drivebc.ca/mobile/weather/index.html. MoTI weather data less than one month old can be made available if a request is placed directly with the main MoTI office (avalanche branch) in Victoria.
Parks Canada Remote Weather Stations. Parks Canada maintains a network of high-elevation weather stations in the mountain parks. Current weather data up to 24 hours are available on their website. Data older than 24 hours must be requested from Parks Canada’s main office.
Private Weather Stations. Other operations, such as ski hills, mechanised skiing operations, and industry operations may also be able to provide historical weather data. In these cases, you will need to contact the operation directly.
Studying the weather associated with previous extreme or unusual avalanche events will give you a better understanding of the forecast area, and may help you forecast future extreme events. Important questions such as the following can be answered:
What are the precipitation, temperature, and wind effects of a particular flow pattern in a given area?