Moisture Update - May 20, 2024

Maps 2 & 3: Recent rains come closely on the heels of a widespread wet pattern that has been gripping parts of the province in recent weeks. Since April 1, 2024, most of the east-half of the province has received at least 80 mm of moisture and many lands south of the TransCanada Highway have seen well over 100 mm (Map 2). This abundance of moisture has also been seen across the mountains and foothills, extending from the Yellowhead Highway as far as the US Border. In the 50-days since April 1, 11 stations have reported over 200 mm, with the highest amounts reported at White Rabbit Creek Station at 286 mm, Spionkop Creek Station (near Waterton Lakes) at 254 mm, and Medicine Lodge Station (Cypress Hills) at 245 mm. The east-half of the province has seen mostly above normal moisture, with several pockets of once in 50-year highs located across a wide swath of land, from Fort McKay (north of Fort McMurray) to as far south as Medicine Hat.  

In sharp contrast, some areas of the North West Region and south-western Peace Region are still below normal (Map 3), with several pockets in the southern Peace Region receiving less than 30 mm. The lowest amounts were recorded at the Beaverlodge Station, where only 20.6 mm has fallen since April 1. This is roughly 50% of the average expected for this time of year. Over the last 180-days, Beaverlodge recorded only 58 mm, which is 40% of normal (145 mm), representing a once in 50-year dry spell.

Maps 4 & 5: Despite recent rains, much of the Peace Region is still well below normal for soil moisture (Map 4), with most of the agricultural areas still suffering from a chronic lack of moisture stemming back to the latter half of 2023. Notably, a large area west of Red Deer has generally missed out on much of the recent moisture. Fortunately, this area is typically one of the wetter zones in the province, and the latter half of May, and all of June, July, and August, are usually relatively wet.  

Ample precipitation, across the east-half of the province, has seen soil moisture reserves trending to at least near normal. Some pockets of once in 50-year highs are emerging across the Southern Region and also on lands around Slave Lake (Map 4). In these areas, continued, sustained rainfall could lead to flooding. Map 5 shows several areas around Lethbridge and across north central parts of the province, where current soil moisture reserves are nearing 160 mm or more (medium blue). These areas have reduced capacity to absorb additional heavy rains and are at a higher risk for local flooding should they come soon or if it continues to be chronically wet.