As up to 30,000 motorcyclists gear up to join Saturday's annual Spring Flood Run in southeastern Minnesota, the Minnesota Department of Public Safety is urging drivers and riders to take extra precautions.

The charity event — which is known as the unofficial start of motorcycle-riding season — takes riders along the Mississippi and St. Croix Valley roadways between the Twin Cities and Winona with stops at small cities in between.

This year's volunteer-run fundraiser will benefit Gillette Children's Hospital.

The event began in 1965, when 12 motorcyclists rode to Winona to help sandbag during a flood. Since then, the fundraiser has become one of the oldest and largest motorcycle runs in the country.

Law enforcement officers from southeastern Minnesota and the Minnesota State Patrol will be patrolling the area during the event.

"Riders should be doing everything they can to prevent crashes and make it home safe from every ride," Lt. Tiffani Nielson of the State Patrol said in a news release. "Ride smart, ride sober and wear protective gear. Even though other drivers should be looking twice, be aware that they might not always see you."

Officials are encouraging motorists to always look twice for motorcyclists, give riders room and check blind spots before switching lanes. Motorcyclists are asked to be prepared for inattentive drivers and to wear helmets and brightly colored protective gear for better visibility.

There are more than 236,000 registered motorcycles and more than 414,000 licensed operators in Minnesota, according to the State Patrol.

Haley Hansen is a University of Minnesota student on assignment for the Star Tribune.