Snow Conditions Commentary

May 16, 2018

A bi-weekly commentary of snow conditions based on readings from the BC Automated Snow Weather Station (ASWS) network is published during the snow season.

This is a preliminary review of available May 15th manual snow survey and automated snow weather station data. A complete report based on all survey data will be released on Tuesday May 22nd, which will include a more detailed analysis and summary of snow pack conditions and outlook for the province.

Weather

Weather over the past two weeks has been extremely hot, with temperatures in the 5-10˚C above normal range across most of the province for most of that period. Heavy rainfall in the Okanagan, Shuswap, Boundary and Kootenay occurred over the May 9-10 period, and exacerbated flood conditions in those regions.

Snowpack

Dramatic snow melt has occurred over the past 2 weeks in response to extreme temperatures. Snow basin indices have declined significantly in most areas of the province, reflecting this rapid melt. Snow packs have largely been depleted from low elevation areas. Mid-elevation areas have melted approximately 30-60% of the snow pack, and upper elevations have melted 10-30%. On-going flood risk from this season’s snow pack is primarily associated with the remaining mid-to-upper elevation snowpack. In low-to-mid elevation watersheds, snow melt risks have subsided. Except for larger lake systems of the province, or watersheds draining high mountain terrain, risks from snow melt are expected to last another 1-2 weeks. Future risks of flooding beyond that period will largely be the associated with heavy rainfall events.

 

Table 1 - BC Snow Basin Indices (Preliminary) – May 15, 2018

Basin

% of Normal

Basin

% of Normal

Upper Fraser West

NO DATA

Boundary

137

Upper Fraser East

74

Similkameen

112

Nechako

90

South Coast

109

Middle Fraser

84

Vancouver Island

79

Lower Fraser

105

Central Coast

93

North Thompson

92

Skagit

NO DATA

South Thompson

90

Peace

45

Upper Columbia

97

Skeena-Nass

94

West Kootenay

143

Stikine

9

East Kootenay

133

Liard

NO DATA

Okanagan

126

Northwest

NO DATA

Manual snow survey data is published as it becomes available, and both manual and automated snow station data can be found at: https://www2.gov.bc.ca/gov/content/environment/air-land-water/water/water-science-data/water-data-tools/snow-survey-data

 

Download the detailed listing of all snow pillows here: ASP Weekly Summary.

The finalized Snow Survey and Water Supply Bulletin is planned for release by end of day May 21st 2018. It includes manual measurements from approximately 150 snow survey sites and is considered a more thorough representation of provincial and regional snow packs.