A recent storm in southern Manitoba brought unexpected dark, muddy rain instead of the anticipated clear showers to cleanse the post-winter dirt. Environment Canada issued blowing dust and wind warnings for various areas in southern Manitoba and Saskatchewan. The dusty rain left vehicles coated in grime, resembling they had traveled down a dirt road.
The storm, with strong westerly winds gusting up to 90 kilometers per hour, led to reduced visibility and poor air quality in certain locations. Blowing dust, caused by winds lifting dust particles into the air to mix with rain before falling back to the ground, resulted in the dirty rain phenomenon.
University of Manitoba climatologist Alex Crawford explained that the dust mixes with rain either in the clouds or during the rainfall, leaving a dusty residue on surfaces when the rain evaporates. Despite the inconvenience caused by the presence of dust in the air, particularly for individuals with respiratory issues, Crawford mentioned that dirty rain does not pose significant health risks.
Crawford highlighted that the storm’s atmospheric pressure, measuring 981 hectopascals, indicated a strong storm, lower than the majority of storms typically experienced in Winnipeg at this time of year. He attributed the dusty rain to the impact of a massive storm system originating from drought-affected areas in the western United States, which funneled dust clouds into Winnipeg.
While the storm’s strong winds played a role in the phenomenon, Crawford emphasized that the main cause was the influx of dust from the drought-affected regions, as tracked through the Windy weather app. Despite the unusual weather event, the climatologist reassured that dirty rain is not more hazardous than regular atmospheric dust.