Water Supply Outlook for Alberta

April 2007

Plains Runoff Outlook

The risk of overland flooding and flooding of smaller streams and rivers in Northern Alberta is high as a result of record to near record snowpack (Figure 1). Snowpack in northern Alberta is similar to that measured in 1974 and 1997, both years which recorded major flooding in plains areas. The severity of flooding this year will depend on when and how snowmelt occurs. Delayed spring conditions or a long period of warm sunny weather will worsen flooding. Snowmelt will not flood major rivers such as the Peace, Athabasca, or North Saskatchewan, however ice jams may occur and cause localized flooding.

Flood risk is highest in the Grande Prairie - Peace River area where nearly half the snowpack measurements broke records by a significant margin, and across North Central Alberta (Edson - Slave Lake - Cold Lake - Lloydminster area) where almost all snowpack measurements were among the five highest on record and soil moisture is generally normal or higher. Flood potential is also high in the remainder of northern Alberta (High Level, Fort McMurray and Fort Chipewyan area). Snowpack in this area is very high but not as extreme, and soil moisture is low.

Alberta Environment is monitoring these areas very closely, and will issue flood advisories as required. Also check the Forecaster's Comments on the department website throughout the month for the most current conditions.

Plains snowmelt has generally finished for the season for the province south of a line through Rocky Mountain House and Lloydminster.

For technical enquires about this web page please contact Alberta Environment - Environmental Management Water Management Operations Branch at AENV-WebWS@gov.ab.ca