Calgary weather: Why recent snow won't fix drought conditions

The Calgary area was the literal and figurative site of the bulk of last week's snow.

According to Environment Canada and Climate Change (ECCC), Calgary received just over 35 centimeters of snow over four days from Tuesday to Saturday.

These findings add to Calgary's unusually snowy March. Historically, March is Calgary's snowiest month of the year, with a 30-year average snowfall of 22.7 centimeters.

As of March 25, 2024, 62 centimeters of snow had fallen at Calgary YYC International, according to ECCC public records.

Given the recent growing season as well as drought conditions, it may seem like this snowfall will have a significant impact on soil moisture, but unfortunately, the situation is more complicated than that.

This map shows snow depth in Alberta and parts of BC and Saskatchewan. (CTV News)

Local soil moisture in Calgary will see a short-term positive impact from this recent snow, but there are many factors to consider.

If the melt rate is too high and/or the ground is too saturated to absorb more water, some of the melted snow (water) becomes runoff and is diverted to artificial catchments, including stormwater systems.

Because of this – similar to summer rain – it is better to have several days of light, wet rain than one massive downpour in a short period of time.

The flow of our river systems is an even bigger issue, as is the extent of the drought conditions affecting southern Alberta.

Spring runoff has the greatest influence on the river water level in our region.

A slight increase in precipitation in February has improved Agriculture and Agri-Food Canada's Drought Monitor classification for parts of Southern Alberta, although much of the area is still between D2 (severe drought) and D4 (exceptional drought) ratings.

The national agency noted that as of the end of February 2024, “fifty-one river basins, covering more than half of (Alberta's) agricultural land, are reporting water shortages.”

Agriculture Canada explains that low rainfall, above-season temperatures and below-average snowpack have pushed many rivers to “record lows,” with “many reservoirs across the province” below normal water lines.

Drought Update March 26, 2024 from Agriculture and Agri-Food Canada. (CTV News)

Groundwater levels outside of Calgary are also experiencing a steady decline and are “currently at an all-time low.”

Essentially, while this recent snowfall has improved drought conditions, the water is entering the system too late to have a major impact on the city of Calgary.

Low water tables can pose obvious challenges for agriculture, but can also pose health risks due to limited dilution (high concentrations of unwanted materials).

Agriculture and Farm Products Canada noted in its February forecast that “some small municipalities (in southwestern Alberta) have had to truck in water” due to higher demand compared to supply.

Feedback loops can exacerbate these scenarios – for example, higher temperatures often lead to increased evaporation, further reducing water supplies.

Calgary is gradually warming up, climbing above freezing temperatures since last Tuesday.

Wednesday will be the warmest day this week and temperatures are expected to drop again by Thursday.

Light and scattered snow is possible through the weekend, but accumulations are expected to be minimal in Calgary.

Calgary Five Day Forecast for March 26-30, 2024. (CTV News)