Why did the salmon cross the road? To find a mate, of course.

Once a year, chum salmon can be seen swimming furiously across flooded roads along western Washington State’s Skokomish River.

“When we get good fall rain this river overflows its banks ... right around this time,” says Aaron Dufault, a salmon policy analyst at the Washington Department of Fish and Wildlife.

“It’s always kind of a shock to see a nine- or 10-pound salmon crossing the road,” Dufault adds.

The natural occurrence coincides with chum salmon spawning season. While the excess water pools up in puddles on roads or in fields, the salmon often follow the flow, taking them out of the river’s main channel.

“Likely they are in the process of trying to find a mate and a good spot, and their spawning isn't successful unless they are able to make it back to the main stem of the river or some side channels,” Dufault says.

Despite occasionally losing their way, the fall chum salmon population is doing great, Dufault says. The salmon typically begin appearing inland in November, after a journey across the open ocean.

When chum hatch from their eggs, they emerge from the gravel and swim straight out to estuaries, unlike most species of salmon. Other species remain in freshwater for anywhere from three to five years while they put on size.

Additionally, the salmon-crossing-the-road situation is rarely seen with species other than chum, probably because of the timing of the runs, Dufault says.

“It’s pretty impressive how adept they are at swimming with half their body out of the water,” he says. “Their drive to go spawn will take them over some pretty dicey spots and drives them forward.”