This graph shows the precipitation history recorded by the Alberta Agriculture weather station at Hespero, west of Sylvan Lake from Jan 1 to November 13, 2018. The shortfall is 170 mm (0.17 m) of precipitation compared to the long term average. We assume that those observations at Hespero are representative of those for our watershed as it is the closest station, and generally upwind:
That season-long deficit is of 0.17 metres of precipitation is equivalent to 7.1 million cubic metres of water that did not fall on the lake surface area of 42 million square metres. Note that the lake level dropped by 0.28 metres during 2018, mainly by evaporation off the surface.
Conditions in Central Alberta were extremely dry through the growing season. Low daily precipitation rates also prevent soil saturation and runoff into tributaries so surface flows and discharge into the lake has been negligible.
This is the final graph for 2018. Readers who want current data should view this web page: https://agriculture.alberta.ca/acis/alberta-weather-data-viewer.jsp
The Alberta Agriculture Moisture Situation Updates are also posted for easy access: http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/ppe9917
This is the final monthly weather summary for October:
Get the “big picture” from the Alberta Agriculture’s Climate Information Service: https://agriculture.alberta.ca/acis/