Blizzard shuts down I-35 from Ames to Clear Lake; snow squalls add to dangerous travel

AMES, Iowa — Blizzard conditions forced the closure of Interstate 35 from Ames north to Clear Lake after a cold front swept into Iowa Sunday, bringing heavy blowing snow and intense winds.

The storm also triggered snow squalls across central and eastern Iowa, creating sudden, dangerous drops in visibility and rapidly changing road conditions. National Weather Service meteorologist Rod Donovan says snow squalls are typically brief but can be especially hazardous because they can arrive quickly and dramatically worsen travel in a short time.

Donovan says the cold air behind the front also caused areas of flash freeze, turning wet or melting road surfaces into ice in a matter of minutes.

While snow squalls usually last around an hour, blizzard conditions are longer-lived — typically three hours or more — and the combination of snow and strong winds led to the I-35 closure.

Conditions remained rough into Monday morning, with Donovan warning of bitter wind chills — near 25 below in northern Iowa and 5 to 15 below across central and southern parts of the state — along with continued hazardous travel.

There is some better news ahead: Donovan says Iowa should see a modest warm-up on Tuesday, with highs expected in the upper 20s to mid-30s, which could help improve road conditions as temperatures rise.

Even so, he says the cold makes it harder for DOT anti-icing treatments to work effectively, and blowing snow will continue to be a problem in exposed areas.

Drivers are urged to check road conditions before traveling and to use extreme caution if they must be out.