Ministry of FLNRO

Snow Survey and Water Supply Bulletin - June 15th, 2017

The June 15th snow survey is now complete. Data from 3 snow courses and 71 automated snow weather stations around the province, collected by the Ministry of Environment Snow Survey Program and partners, and climate data from Environment Canada have been used to form the basis of the following report.

Click here for the Snow Survey and Water Supply Bulletin as a PDF file.
Click here for the complete June 15, 2017 Snow Survey Data.

Weather
Weather in June has been mixed. Temperatures have been generally above normal, particularly in southern, central and north-east BC. A heavy rainfall event in northern BC in early-June has led to above-normal precipitation. Despite significant rainfall through the spring, areas of southern BC have generally experienced below-normal precipitation over the past few weeks.

Snowpack
Snow packs are depleted at approximately half of the snow monitoring locations across the province as of June 15th. At high elevations, snow is still present, with typical snow water equivalent amounts in the 150-600 mm range.

Snow basin indices are mixed for the June 15th period. Since very few manual snow surveys are collected on June 15th (historically and for the 2017 survey period), snow conditions are largely interpreted from automated snow weather station data. As a result, many basins have limited data to assess snow basin index values.

Table 1: BC Snow Basin Indices – June 15, 2017


Basin

% of Normal

Basin

% of Normal

Upper Fraser West

NO DATA

Boundary

38

Upper Fraser East

36

Similkameen

32

Nechako

NO DATA

South Coast

189

Middle Fraser

162

Vancouver Island

68

Lower Fraser

210

Central Coast

NO DATA

North Thompson

130

Skagit

NO DATA

South Thompson

115

Peace

36

Upper Columbia

99

Skeena-Nass

NO DATA

West Kootenay

136

Stikine

NO DATA

East Kootenay

109

Liard

NO DATA

Okanagan

NO DATA

Northwest

NO DATA

  1.  ‘No Data’ indicates that no basin index snow surveys were conducted within the basin during this survey period, or no snow was recorded at sites with surveying.

 

In regions of the province with higher elevation, or deeper seasonal snow accumulation, snow basin indices are nearer to normal, or above normal. This includes the mountainous regions of the Middle Fraser, Lower Fraser, South Coast, Columbia and Kootenay. Elsewhere, low June 15th snow basin indices are present and largely reflect the rapid melt of snow through the May and early-June period.

Streamflow
Freshet runoff echoes the pattern in snow melt, with many rivers experiencing an early peak due to rapid snow melt in May. Flows through the BC Interior have begun to recede from their freshet peak levels. In most areas of the province, flows have receded to more typical levels for this time of year. In areas of northern BC and the South Interior, below normal flows are beginning to occur as a result of low snow packs and early snow melt.

Outlook
The Climate Prediction Centre at the U.S. National Weather Service/NOAA has identified ENSO-neutral conditions at present, with a slightly favoured outlook for ENSO-neutral conditions through the fall of 2017. Seasonal forecasts from Environment Canada are indicating an increased likelihood of above normal temperatures over the summer period (June through August).  

Across the province, snow-melt driven flood risk for the remainder of the season is minimal; flooding from extreme rainfall is still possible.

The early end to the freshet this season is expected to lead to a transition to summer flows earlier than is usual, and may result in lower than normal flows later in the summer. In some areas, this transition has been taking place, particularly in areas that had low snow packs this year (i.e. northern BC) and areas where snow influence on streamflow ended earlier (e.g. smaller streams in the South Interior). Risks for low flows this season are elevated in northern BC due to lower than normal seasonal accumulation of snow. Across the province, summer rainfall will be a dominant factor in whether or not low flows occur.

This is the final Snow Survey and Water Supply Bulletin for the 2017 season. The River Forecast Centre will continue to monitor streamflow and weather across the province, and issue Water Supply and Streamflow Bulletins throughout the summer as conditions warrant. Seasonal information on drought and drought levels is available on the BC Drought Information Portal.

BC River Forecast Centre
June 22, 2017