Water Supply Outlook for Alberta

September 2002

August 2002 Precipitation

Near-normal precipitation in August was recorded in the southern half of the province while northern areas recorded below-normal precipitation values (Figure 1). Areas around Medicine Hat, including the Cypress Hills, recorded much-above-normal precipitation (Figure 2), with precipitation totals in excess of 140 mm in August (Figure 3).

Summer Precipitation (May 1 to August 31, 2002)

Summer precipitation (May 1 to August 31, 2002) in areas north of Calgary remains much-below-normal despite near normal precipitation in August (Figure 4). One exception is near Edson, which received 106 mm in a six-hour period in late August, which brought the summer precipitation total to much-above-normal. A major storm event brought significant precipitation to southern Alberta in early June, where the Waterton Park and Milk River areas received in excess of 300 mm during the event. As a result, precipitation totals remain much-above-normal south of Calgary (Figure 5) with the highest amounts in the Upper Oldman and Highwood River basins, where over 650 mm of precipitation has been recorded since May 1 (Figure 6).

Winter Precipitation (November 1, 2001 to April 30, 2002)

Winter precipitation (November 1, 2001 to April 30, 2002) is near normal in most areas west of a Grande-Prairie-Whitecourt-Red Deer-Lethbridge line and below-normal in areas east of this line (Figure 7). Precipitation in April helped raise winter totals closer to normal values, particularly in southern Alberta (Figure 8). Areas along the eastern side of the province received much-below-normal precipitation and the higher elevations in the mountains have recorded above-normal values (Figure 9).

Fall Precipitation (September 1 to October 31, 2001)

Fall Precipitation was below-normal to much-below-normal in most areas of the province (Figure 10) with southern areas recording much-below-normal values (Figure 11). As a result of the low precipitation totals (Figure 12), soil moisture conditions remain very dry in most areas of the province. A map showing soil moisture conditions in the province is available from the Alberta Agriculture website located at:

Long-Lead Precipitation Outlook

Environment Canada's long-lead precipitation forecast on September 1 for the September to November period indicates above-normal precipitation in the province with near normal precipitation in northwestern Alberta. The forecast for the winter period (December to February) is for below-normal precipitation in the southern two-thirds of the province and normal in the northern portion of Alberta. Environment Canada's long-lead precipitation outlook is available from their website located at:

The National Oceanic and Atmospheric Administration (NOAA) is forecasting equal chance of below-normal, normal or above-normal precipitation in the fall of 2002 (September to November). NOAA is forecasting below-normal precipitation for the southern portion of the province during the winter (November through February) period. NOAA's long-lead precipitation outlook is available from their website located at:

NOAA indicates that a weak El Nino has developed in the tropical Pacific. Current indications are that the strength of this El Nino event will be less in magnitude than the event that occurred in the winter of 1997-98. The significance of an El Nino event to the province of Alberta is that winter precipitation is typically below-normal during such events. The last major El Nino event occurred in the winter of 1997-98.

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