DES MOINES, Iowa — Water is a catastrophic force in its natural state already, but once frozen it can cause even more mayhem.
Two years ago, ice jams caused the Trestle to Trestle Bridge in Johnston to collapse. A week later, Story City's iconic swinging bridge was damaged.
Ice jams can also cause some major flooding.
“An ice jam is the ice that is sitting on the surface of the river and if it melts quickly, it breaks up into large chunks and creates a temporary dam," said A.J. Mumm, director of the Polk County Emergency Management. "That water backs up behind that ice jam and has a large potential [to] do damage with flooding.”
Mumm said ice jams happen every two-to-three years. He said the risk of river flooding this year is reduced, but that doesn't mean it's a zero risk.
Numerous factors like drought, snowpack, soil moisture, frost depth, and current streamflow all play a role in spring river floods.
“The extreme temperatures we’ve had allow for the thickness of the ice to become very significant. If we have a gentle thaw, a nice slow warm like we all want, then it probably won’t be an issue," explained Mumm.
Central Iowa is expecting to be in the 30s this weekend, which will allow for a slower thaw.
However, another threat from ice looms over homeowners' heads— literally.
Ice dams are typical this time of year and form on roofs. An ice ridge forms at the edge of a roofline and prevents melting snow from draining off.
The water can back up under shingles and damage walls, ceilings and insulation. Home improvement stores carry a number of products to prevent ice dams.
WATCH: The snow is piling up on the sides of the roads and the City of Des Moines has a plan on what to do with it.