Intermittent precipitation expected for central and southern Alberta until Thursday

Heavy, wet snow turned to slush in many communities, including Calgary, early Tuesday.

By the middle of the morning commute, most roads were just wet as traffic picked up and road crews applied melting-agents where needed.

As expected the upsloping nature of this large system has produced highly variable precipitation totals – and this is expected to continue with the centre of the main low pressure system situated along the southern portion of Saskatchewan.

Moisture entering the low has been rain with the main source being the southeastern Pacific. But as that rain is wrapping around the low it has been encountering colder air from the north and turning into snow.

The counter-clockwise rotation associated with this low is then driving precipitation through central and southern Alberta and pushing it back against the foothills, and until this system is pushed out this same scenario will continue to repeat.

Satellite and radar image from April 30, 2024. The white arrows are showing the direction of flow around the low.

On Monday, Environment and Climate Change Canada (ECCC) issued snowfall warnings west of Calgary and a large special weather statement for Calgary and areas along the foothills.

Those advisories were continued Tuesday for most communities and even expanded in some areas. Snowfall warnings may be further expanded on Tuesday and Wednesday as more forecast certainty becomes available.

ECCC issued special weather statements (pink) and snowfall warnings (white) on Tuesday, April 30, 2024.

As of 9 a.m. Tuesday many highways west of Calgary were rated as snow-coved and/or icy by 511 Alberta.

Accumulating precipitation, precipitation types, and rates all likely contributed to the measureable impact to travel throughout those same areas on Tuesday morning. This negative impact is likely to get worse as snow and rain continue throughout the week.

At that same time the 511 Alberta cameras were showing mostly wet roads in southwestern Alberta with accumulating snow west of Calgary along the Trans-Canada Highway.

Daytime highs will remain 9 C to 11 C below average until Friday, with overnight temperatures closer to seasonal.

In their special weather statement Tuesday, ECCC noted precipitation will continue until Thursday morning with the multi-day event totals on the high-end are expected to measure between 10 to 25 centimetres.

“The highest amounts will fall west of Highway 2. The snow will be heavy and wet, and will be mixed with rain in some areas, so total snowfall accumulations will vary widely.”

For the latest ECCC weather advisories click here. For the latest road conditions from 511 Alberta click here.