Snow Survey and Water Supply Bulletin (June 15, 2014)
The June 15th snow survey is now complete. Data from 2 snow courses and 51 snow pillows around the province and climate data from Environment Canada form the basis for the following report.
Click here for the Snow Survey and Water Supply Bulletin as a PDF file.
Click here for the complete June 15, 2014 Snow Survey Data.
June weather has featured episodes of cold upper low systems, which have delivered periods of wet weather, particularly through southern British Columbia. Despite this, precipitation over the first half of June has been below normal to normal across most of the province. Temperatures have been near normal through most areas.
The first two weeks of June has seen on-going melt of the season’s snow pack with 200 mm to 400 mm of snow water equivalent of melt observed at most snow pillows around the province. At high elevation sites (>1500m-1600m), particularly in the Upper Fraser, North Thompson, South Thompson, Columbia, Kootenay, Okanagan, Similkameen and Peace, snow packs are generally above normal. High elevation snow pillows have 20%-60% of the season’s snow pack remaining. In mid-elevation sites, the season’s snow pack has largely melted. This includes the Nechako, Middle Fraser, Lower Fraser, Columbia, Okanagan, South Coast, Vancouver Island, Peace, Skeena and Stikine.
On the major river systems of the province (Fraser, Thompson, Skeena), approximately 50-60% of the forecasted seasonal runoff volume (April-September) has passed. In May, many rivers had above-normal flow due to warm weather. In the first half of June, depletion of mid-elevation snow packs has led to river levels dropping to near normal levels for the time of year. In the Peace, stream flow in many tributaries has dropped to below normal (50-80%). On Vancouver Island, stream flows have dropped to below or well-below normal levels (20-80% of normal).
Snow packs have now diminished to the level that flood risk due to snow melt is now unlikely across the province. Flood risk due to extreme rainfall remains a possibility.
In areas with depleted snow packs, stream flows have transitioned, or are expected to transition into lower than normal flow. This is particularly the case on Vancouver Island, South Coast, Middle Fraser, Lower Fraser, Central Coast, Nechako, Skeena, and Peace. These regions are at increased risk for potential low flows this year. With very low snow packs on Vancouver Island this year, watersheds are particularly vulnerable to low flows from hot and dry summer weather.
Seasonal forecasts from Environment Canada continue to indicate an increased likelihood of above normal temperatures across British Columbia, particularly through the south and south-west parts of the province.
This is the last Snow Survey and Water Supply Bulletin of the year. The River Forecast Centre continues to monitor snow pack, weather and stream flow conditions across the province. Updates on stream flow conditions will be made in the Water Supply and Stream flow Bulletins which will be released through the summer as conditions warrant. Low flow advisories will be issued if required.
Produced by: BC River Forecast Centre
June 23, 2014