Ministry of Environment
Current Snow Survey and Water Supply Bulletin
The May 15th snow survey is now complete. Data from 34 snow courses and 53 snow pillows around the province and climate data from Environment Canada have been used to form the basis for the following reports.
The entire document including text and data can be viewed as an Adobe pdf file.
The detailed snow survey data can be viewed as an Excel file or PDF file.
Weather
Cool and dry conditions were present throughout the province through the early part of May. High pressure ridging starting in the second week in May led to two warming periods. The second ridge towards the middle of the month created 3 to 4 days of hot weather, particularly through the Interior, Okanagan-Kettle, Similkameen, and Kootenays. In general conditions have been drier than normal through the first half of May.
Snowpack
The snow melt season is now proceeding steadily. A number of hot spells through late-April and early-May has led to significant dwindling of the mid-elevation snow pack, particularly in the Similkameen, Okanagan, Kettle, Kootenay, and Interior. Despite the warm weather and snow melt at mid-elevations, snow melt has been limited at upper elevation sites.
Significant snow packs are still present at high elevations across the province, with above average to well above average snow basin indices in all regions except the Okanagan. The delay in snow melt season, particularly in high elevation locations, has led to an increase from May 1st snow basin index values in the Upper Fraser, Middle Fraser, Nechako, North Thompson, South Thompson, Kootenay, Similkameen, South Coast, Peace and Skeena-Nass.
BC Snow Basin Indices – May 15, 2012
Basin |
% of Normal |
Basin |
% of Normal |
Upper Fraser |
167% |
Kootenay |
154% |
Nechako |
150% |
Okanagan-Kettle |
95% |
Middle Fraser |
118% |
Similkameen |
113% |
Lower Fraser |
125% |
South Coast |
122% |
North Thompson |
124% |
Vancouver Island |
129% |
South Thompson |
117% |
Peace |
117% |
Columbia |
123% |
Skeena-Nass |
158% |
Outlook
Typically the freshet snow melt season in British Columbia lasts from May to the end of June or early July. With significant snow pack at higher elevation, seasonal flood risk is still present through most regions of the province. Snow packs are still at levels of concern for increased flood risk in the Upper Fraser, Nechako, Columbia, Kootenay, Peace, and Skeena-Nass basins. Basins with nearer to normal snow packs (e.g. Thompson) have normal seasonal flood risk, and under adverse weather conditions, flooding is still a possibility.
Snow melt at mid-elevations through the Similkameen, Okanagan, Kettle and South Interior has led to diminished on-going seasonal risk in these regions.
Above-normal seasonal runoff is expected throughout the province. Currently rivers around the province are, in general, flowing at near seasonal levels for this time of year and are below levels of concern for flooding.
Current 30-day temperature forecasts from Environment Canada are for above-normal temperatures through the southern half of the province. Seasonal forecasts for May through July are for a higher probability of warmer than normal temperature in eastern BC, and cooler than normal in coastal BC. Precipitation forecasts for the May through June period are for a higher probability of below normal precipitation for coastal BC, and normal precipitation through eastern BC.
The River Forecast Centre continues to monitor snow and weather conditions across the Province and when conditions warrant, provides advisories through media releases and on the River Forecast Centre website: http://bcrfc.env.gov.bc.ca/. The June 1st snow bulletin is expected to be released on or before June 11th, 2012.
Produced by: BC River Forecast Centre
May 22nd, 2012
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