Moisture Updates - September 6, 2023

Synopsis

Maps 1 & 2: Since the last report on August 31, 2023, modest rains fell across much of the western portions of the Central Region, and large parts of the the North East and the North West Regions, with many lands receiving between 5 to 10 mm of rain (Map 1), just enough to put a temporary pause on harvest activities in these areas. Once again, most of the Southern Region and the eastern portions of the Central Region and parts of the Peace Region remained dry.

Since September 1st, early fall frosts have occurred over parts of the North East with temperatures dipping below -3C through several areas lying west and north of Lloydminster (Map 2). The Mrynam LITE station, located 40 km east of the town of Two Hills recorded the coldest temperatures on September 5 (-3.8°C) with at least 9 consecutive hours lingering below the freezing mark. Looking back as far as 1961, September 3, marks the earliest appearance of a ‑3°C frost in the area, followed by September 7 for a ‑4°C frost In the western Peace Region the Eureka River AGCM station, located in the Agricultural lands about 120 km northwest of the town of Peace River saw the mercury dip to ‑2.6°C, with freezing temperatures persisting for about 4 hours.

365-Day Precipitation Trends, as of September 6, 2023

Maps 3 & 4: Over the past year, precipitation deficits have been severe across much of the Southern, Central and the north-half of the Peace Regions. Across the Southern and Central Regions, large areas of one in 50-year lows are present, with year over year deficits extending into parts of the North East Region and across most of the Central and Southern Regions (Map 3). Across the north-half of Peace Region several pockets of once in 25 to 50 year lows are present, in some cases, tempered on this map by recent rains. Across portions of the South, a total of 9 stations recorded less than 150 mm over the past year (Map 4). The lowest accumulations were recorded just north of Dinosaur Provincial Park, at the Wardlow AGCM station (115.2 mm), which is about half of the 1961-2022 average (320 mm) for the area. Across the extreme northern Peace Region, a large area has received less than 300 mm, with the lowest recorded precipitation accumulations found at the La Crete AGCM station (242.2 mm) which is well below the 1961-2022 historical average of 400 mm.

Soil Moisture Reserves, as of September 6, 2023

Map 5: Soil Moisture reserves have recovered to at least near normal across most of the North East, North West and Peace Regions (Map 5). Across the Central and Southern Regions soil moisture reserves are near normal in only a few areas, most of which have received 20-40 mm within the last 30-days. Elsewhere most of the other lands are estimated to exceed once in 3 to 6 year lows,. Bear in mind this time of year marks a low point in the annual soil moisture regime and soils at this time of year are usually “bone dry” following the normally hot dry months of July and August. As a result, very little moisture is needed to change moisture map classifications. As such, Map 5 tends to understate the severity of the prolonged dry spell (Map 3) that has persisted through the Central and Southern regions, since at least mid-summer last year, and in some locales even over the past several years.