Hikers are flocking to Washington's North Cascades to see larch trees turn gold, and the crowds are causing trouble along Highway 20, FOX 13 Seattle and Cascadia Daily News reported.

Unlike most conifers, larches turn golden in the fall and then shed their needles. The show lasts about two to three weeks, both outlets reported. The nickname for the rush is "Larch Madness."

Trailhead parking fills up fast, so some visitors leave their cars on the shoulder of the highway, FOX 13 reported. The Washington State Department of Transportation said Highway 20 is a remote, two-lane mountain road that was not built for that.

"People are trying to enjoy the trees with almost nowhere to park," Summer Deerey of the transportation department told FOX 13. The state has cut the speed limit to 45 mph in the area and put up no-parking signs. Drivers who park in the wrong place could face fines of about $50 and could have their cars towed, FOX 13 said.

The Washington State Patrol said the problem is also pulling troopers from Omak to the mountain pass, FOX 13 reported.

Cascadia Daily News said a backcountry ranger estimated that 6,000 people visited the trails on a recent Sunday. Maple Pass is by far the busiest trail in the area during larch season, the paper said. Rangers have posted staff and volunteers along trails to keep people on the paths.

The crowds are also good news for towns in the Methow Valley, which had a hard year of fires, floods and little snow, Cascadia Daily News reported. Hotels are booked and restaurants have waiting lines, the paper said.

Officials told FOX 13 that weekends are the busiest and urged visitors to have backup plans.

What we know: Larch crowds are filling Highway 20 trailheads, and the state has cut speeds and warned of fines.
What we don't: Whether officials will add permits or other limits in future years.