Saturday, April, 8, 2023 | 7:19 am
Freshet is a seasonal increase in rivers and streams water flow that occurs during the spring. Temperature fluctuations and winter precipitation amounts, combined with snowmelt and rainfall are key factors that affect the intensity of spring freshet.
In winter, snow accumulates and stores large amounts of water in the snowpack. As temperatures rise in the spring, the snowpack begins to melt, and water flows down into rivers and streams, leading to increased water levels and the onset of spring freshet. However, if temperatures rise too quickly, it can cause the snow to melt rapidly, leading to a sudden surge of water that can overwhelm rivers and streams, and cause flooding.
Heavy rainfall during the spring can add to the already high-water levels, further increasing the risk of flooding. Even a small amount of rainfall during freshet can cause water levels to rise rapidly due to the already saturated ground from melting snow.
Frozen ground and ice jams can also contribute to flooding by impeding the natural flow of water in rivers and streams. When the soil and rock are frozen, the water cannot penetrate the ground, leading to sudden and significant increases in water levels. Ice jams occur when chunks of ice accumulate in a river or stream, blocking the flow of water and causing water to overflow the banks and flood surrounding areas.
Managing the risk of spring flooding is essential to protect communities and infrastructure. It is important to closely monitor temperature fluctuations and precipitation levels during spring freshet. Stay informed by checking your local weather forecasts and know where to find flood resources for your community.
For more information on how to prepare and what to do before, during, and after a flood, visit the Get Flood Ready website.
Written and released by Environment and Climate Change Canada.