Environment Minister Barry Penner says British Columbia has experienced an unusually warm and dry winter, and with the below average snowpacks, there is potential for water-supply challenges to develop this summer.
Weather across B.C. over the winter has been variable, with the effects of a moderate El Niño dominating weather across much of the province for the past three months. Much of central and southern B.C. experienced well above normal temperatures during January, February and the first half of March. As a result of the unseasonably warm weather, melt of low- and mid-slope snow occurred in most areas of the Coast and Interior. The last week of March brought a change in weather, with temperatures moderating downward to be near or slightly below seasonal normal.
Precipitation has been variable over the winter. For the South Coast, a series of Pacific frontal storms during January brought heavy rain. These storms also allowed significant snowpacks to develop on some high- elevation areas on Vancouver Island and the South Coast. February and the first half of March had below normal precipitation, but then frontal storms in late March produced further snow accumulations. For the Interior, snowfall from January to late March was well below normal. During late March, frontal storms arising off the Pacific swept across the Interior, bringing heavier than normal snowfall to some areas.
Typically, by April 1, more than 95 per cent of the winter's snow has accumulated. This year as of April 1, with the exception of high- elevation areas on Vancouver Island and the South Coast, snowpacks across B.C. are all below normal.
Basin snow water indices across B.C. vary from a low of 64 per cent of normal in the Similkameen and East Kootenay basins to a high of 99 per cent of normal on Vancouver Island. Basin snow water indices declined in many basins during March (including the Upper Fraser, Nechako, Mid Fraser, North Thompson, South Thompson, Nicola, Columbia, Okanagan and Kettle). A few basins experienced increases in their snow water during March (including the South Coast, Vancouver Island, Peace, Skeena and Nass). In most basins, low- and mid-elevation snow is absent or well below normal.
Overall, much of central B.C. (Fraser, Thompson, Peace) has 85-90 per cent of normal snowpack. Southern B.C. (Nicola, Okanagan, Kettle, Similkameen, Kootenay) has 65-85 per cent of normal snowpack. The East Kootenay and Similkameen basins stand out as having particularly poor snowpacks. The Skeena and Nass basins are also dry, at only 81 per cent, but they have improved notably from their 73 per cent level a month ago.
Water Supply Outlook:
Conditions as of April 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 and Liard). Water levels on these large rivers typically begin to rise by late April, peaking in late May or early June.
Minister Penner says the below normal snowpack conditions across much of the Interior (Okanagan, Nicola, Kettle, Similkameen, West Kootenay, East Kootenay, Skeena, Nass and Peace) indicate potential for water-supply challenges to develop during the summer. The low snowpack and smaller than normal snowmelt runoff may be reflected in such things as 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. Spring weather has a large influence. To reduce the potential for summer low-flow or drought problems, spring rainfall (April, May and June) will need to be at or above normal. The first week of April has been cool and wet. However, the long-range seasonal forecast from Environment Canada is for warmer than normal weather over the next three months.
For additional information, go to: http://www.env.gov.bc.ca/rfc/index.htm
In December 2009, the B.C. government officially embarked on a process of modernizing B.C.'s Water Act with the launch of the Living Water Smart blog. Living Water Smart: B.C.'s Water Plan outlines the B.C. government's vision and plan to keep B.C.'s water healthy and secure for the future. The plan uses a variety of measures including planning, regulatory change, education and incentives to ensure B.C.'s water resources are protected and sustainable.
To check out the site or post a comment on the blog, go to: http://www.livingwatersmart.ca/