Calgary is no stranger to extreme weather. Recent climate patterns suggest that both floods and droughts are becoming more common each season.
A majority of Calgary’s water supply comes from snowpack in the Rocky Mountains. When temperatures spike over a short period, the snow melts rapidly. That sudden surge can trigger flooding. At the same time, this early snow melt reduces the water available later in the year, contributing to drought risk.
“The snowpack is like a savings account,” said Mount Royal University ecosystem scientist Felix Nwaishi. “If it melts too quickly, you can see flooding first and drought later because the stored water is gone.”
According to the City of Calgary’s long-term resilience page, the city receives little rain, leading to droughts, while snowmelt and sudden heavy rainfall can also set off floods in the city’s river systems.
In late December 2025, Calgary’s largest water main burst. This main carries about 60 per cent of the city’s treated water. As a result, the city was under Stage 4 water restrictions.
How flooding can lead to drought
Nwaishi said landscape and infrastructure changes have made this problem more unpredictable. Calgary once had prairie potholes, also known as wetlands. The wetlands acted as natural sponges. When there was too much water, they soaked it up, and when things dried out, they slowly released it.
“Wetlands and soil systems act as nature’s shock absorbers,” Nwaishi said. “When you lose them, water moves faster across the land, increasing both the intensity of floods and the speed at which drought conditions develop afterward.”
Over time, urban development has destroyed most wetlands. Roads and houses have replaced soil with concrete, which prevents water from soaking into the ground.
The drier the ground gets, the harder it is for water to soak in. Instead of soaking in, the water runs over the soil, leading to flooding in rivers and drainage systems.
“When heavy rain finally arrives, the water just runs off instead of soaking in,” Nwaishi said. “That increases pressure on rivers and drainage systems and makes flooding worse.”
Warmer winters can lead to faster snowmelt, which affects ecosystem patterns. The fast snowmelt increases the chance of severe drought and sudden flooding.
“The climate patterns are really unpredictable now,” Nwaishi said in reference to the planet’s worsening climate change. “Places that are normally dry may get wet, and vice versa, making it harder to plan.”
Nwaishi explained that protecting and restoring wetlands could help lower the risk over time by slowing water movement.
“Even small steps, like conserving wetlands and letting water soak into the ground, can make a big difference.”
Nwaishi also emphasized the importance of the community in helping prevent floods and droughts.
“People need to understand the role they play,” said Nwaishi. “Even simple things, like watering your lawn less or conserving water at home, can help.”
Building water resilience
The City of Calgary’s long-term drought resilience plan lays out how the city is working to prevent drought. The plan focuses on reducing water demand overall by protecting its water supply, upgrading infrastructure, and preparing for future droughts while maintaining healthy landscapes.
“Canada has a significant proportion of the world’s freshwater, and we can’t take it for granted,” said Nwaishi.