That sure was a cold winter. Thankfully, the weather is warming up and spring arrived last Wednesday, March 20.
As the weather warms, snow melts and runs down streets and hillsides and forms some big puddles. Unfortunately, not much water will soak into the ground right away.
That’s because the ground was frozen during the cold days of winter. Water in the soil, rocks and in between them froze hard. When it freezes, the water expands to take up more room. That’s how we get frost heaves — like when you see a sidewalk pushed upward — and potholes.
In Montana, the ground can freeze as far down as 40 inches in western Montana — more than 3 feet — and up to 70 inches in eastern Montana, almost 6 feet deep.
Until that ground thaws, meltwater runs off, traveling into creeks, small streams and then rivers. Montana has devices placed on rivers around the state that show how high, or low, the water is flowing. The devices, called stream gauges, can be found online at the U.S. Geological Survey's website at https://waterdata.usgs.gov/mt/nwis/.
At this time of year it can be interesting to check on your favorite river and look at the line that charts the water going up and down. When there are warm days, the line will rise very steeply as snow melts. Often at night, when the sun goes down and the air temperature cools, the line will go down.
You can even see when an ice dam forms. When ice melts away from the edge of a river and floats downstream, it can sometimes bunch up and create a dam. The water rises very quickly behind the dam when this happens, while the water below the dam drops.
When the pressure gets too great, or the water wears out a part of the ice dam, it will break and water will gush out. This is evident too as a large increase in water very quickly below the dam, while above the dam the water drops.
With water high, ice breaking loose and mud puddles forming to unknown depths, this is a good time to be careful around water. Luckily it won’t be too long, and we’ll be out on the beach, swimming and enjoying what water is left.
— Brett French, firstname.lastname@example.org