Environment Minister Barry Penner says below average snowpacks across British Columbia indicate significant potential for low stream flows and water-supply shortages to develop this summer.
As a result, Penner says the B.C. government is developing a 2010 Drought Response Plan to guide government actions for low stream flows and drought conditions. Given the current low snowpack conditions, notice of potential drought is included in this bulletin, although should wet weather materialize in May and June, it could reduce the risk.
The peak of the winter's snowpack has accumulated and the melt has begun. Snowpacks have declined in most areas during April as a result of drier than normal weather. With the exception of high elevation areas on Vancouver Island and the South Coast, snowpacks across B.C. are all below normal. Snowpacks in the South Interior (Nicola, Okanagan, Similkameen, West Kootenay, East Kootenay, Lower Columbia) and in the Northwest Interior (Skeena, Nass) are substantially below normal.
The snowpack information indicates significant potential for low stream flows and water supply shortages to develop in these areas during the summer. Precipitation over the next month will determine the likelihood and extent of drought over the summer.
Basin snow water indices across B.C. vary from a low of 37 per cent of normal in the Similkameen to a high of 105 per cent of normal on Vancouver Island. Basin snow water indices declined across the Interior during April. Vancouver Island and the South and Central Coast experienced increases in water indices during April, as a result of being affected by frontal storm systems. In most basins, low- and mid-elevation snow is already absent or well below normal, following the unusually warm weather and melt from January to mid-March.
Overall, much of central B.C. (Fraser, Thompson, Peace) has 80-90 per cent of normal snowpack. The South Interior (Nicola, Okanagan, Kettle, Similkameen, Kootenay) has 37-76 per cent of normal snowpack. The Skeena and Nass basins are also drier than normal, at only 61 per cent, a notable decline from their 81 per cent level a month ago.
Water Supply Outlook:
Conditions as of May 1 indicate a likelihood of well below normal freshet runoff during May and June, and low risk for freshet flooding in the major river basins (Fraser, Thompson, Skeena, Bulkley, Nass, Peace, Liard). Water levels on these large rivers began to rise in late April, and are expected to peak by late May or early June.
The well-below-normal snowpack conditions across much of the South Interior (Okanagan, Nicola, Kettle, Similkameen, West Kootenay, East Kootenay), along with the Skeena, Nass, and Peace River basins in the north, indicate potential for low stream flows and water-supply challenges to develop during the summer. The low snowpack and smaller-than-normal snowmelt runoff are likely to be reflected in lower-than-normal lake and reservoir levels, lower-than-normal recharge of groundwater aquifers and lower than-normal river levels during summer.
Snow conditions at the end of the winter comprise only part of the peak flow and water supply forecast picture. Weather during May and June has a large influence. To reduce the potential for summer low-flow or drought problems, rainfall during May and June will need to be at or above normal.
Much of the South Interior (including the Nicola, Okanagan, Kettle, Simikmaneen, East Kootenay, West Kootenay and Lower Columbia) are currently classified at Drought Level 3 (very dry conditions), where low stream flows and water supply shortages are highly probable unless significant rainfall occurs during May and June. In these areas, water conservation is urged. Water restrictions at the local level should be considered and drought management plans should be reviewed.
Much of the Central and North Interior (including the South Thompson, Cariboo, Upper Fraser, Skeena, Nass, Bulkley, and Peace) are currently classified at Drought Level 2 (dry conditions). These areas have early indications of potential low stream flow and summer water supply shortages. Voluntary water conservation is urged, as well as planning at the local level and use of tools such as drought management plans.
As part of the engagement sessions that were held in various regions of the province in preparation for a drought season, the government is hosting a drought response workshop in Cranbrook on May 13. For more information on this workshop http://www.env.gov.bc.ca/wsd/public_safety/drought_info
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For additional information on the snowpack data,CLICK HERE
Living Water Smart: B.C.'s Water Plan outlines the government's vision and plan to keep B.C.'s water healthy and secure for the future. For more information, CLICK HERE