Tuesday's big snowfall in the Twin Cities has left local streets less passable, and that will add an extra challenge for bicyclists participating in a disaster relief trial designed to show how bicycles can be used to reach victims when traditional response vehicles can't get through.

Nearly 20 to 30 bicyclists set off from the Commons Hotel on the University of Minnesota campus at 8:30 a.m. Wednesday to complete realistic assignments to test the effectiveness of using bicycles to respond to emergency incidents under winter conditions, said Steve Durrant, who is organizing the drill in conjunction with the 2016 Winter Cycling Congress, which runs through Thursday at the U.

Cyclists using two-wheelers with fat tires and studded tires will ride up to 20 miles along the Minneapolis and St. Paul bikeway systems and on neighborhood streets to reach 10 to 12 checkpoints. That is where they will complete tasks such as delivering medicine or searching for a missing person, Durant said.

At times, cyclists will have to transport 50-pound sandbags as they pedal along, Durrant said.

In Wednesday's exercise, the simulation presumes that power has been knocked out over a widespread area and traffic is gridlocked, preventing ambulances, police and fire crews from reaching disaster scenes.

"Should there be a disaster that affects traffic or infrastructure downtown, having bicycles navigate alternative routes could prove to be an essential resource to perform emergency response activities." said physician John Hick, Medical Director for Emergency Preparedness at Hennepin County Medical Center.

While similar trials have been held during previous cycling congresses, this is the first time it's been tried during the winter. The goal of the exercise is to give emergency responders the thought of using bicycles as another response tool, Durrant said.

The snow, Durrant said, was a "nice coincidence," adding another layer of realism to the exercise.

The Winter Cycling Congress is a three-day conference designed to promote bicycling and walking among people of all ages and abilities through the winter.

Previous congresses have been held in Finland, Canada and the Netherlands.

Tim Harlow • 612-673-7768