Sierra snowmelt: the creek crossings that decide when Fordyce and Dusy open

The site's guidance for the Sierra Nevada says the high passes open late spring and gate with the first snow. The place records are more specific. Fordyce Creek Trail typically opens July through October once snowmelt drops the creek crossings to a passable level. Dusy-Ershim has a short window, usually July into early October, between snowmelt and the first storms. The Rubicon is listed as late June to October, snow permitting either side.

What that means in practice is that the opening date of a Sierra trail is set by how much snow fell the previous winter and how fast it is melting now, not by a calendar. A heavy snow year pushes everything back by weeks. A light one can have the passes clear before the season guidance says they should be. Neither is knowable from a distance, and the forest offices are the ones tracking it.

Fordyce Creek is the clearest example. The place record names the water crossings and Winch Hill 5 as what sets the grade, and in early July the crossings are the obstacle. Snowmelt water is fast, cold and opaque, and the bottom of a crossing that was rock last October can be scoured or filled with debris. The Tahoe National Forest notes that seasonal closures and high water can close the route, and high water is the reason it usually is.

Dusy-Ershim in the Sierra National Forest runs about thirty miles of sustained high-elevation granite through alpine meadows, and meadows are the concern in early summer. A meadow that is saturated with melt water is destroyed by a tire in a way that takes years to recover, which is why the forest posts seasonal closures and why the route stays gated until the ground firms up. A campfire permit is typically needed on the trip.

The Rubicon, managed by El Dorado County, is lower than the other two and usually opens first, but snow lingers on the north-facing sections around Cadillac Hill and the Little Sluice well after the trailheads are clear. The county asks for self-registration and requires a portable toilet under ordinance. Confirm with the managing agency before you go; a trailhead with no gate is not the same thing as a trail with no snow.

Water crossings after snowmelt are the classic way to damage a machine without a mark on it. The maintenance guidance on this site notes that water washes grease out of joints, eats brake pads, and can contaminate a truck or SUV differential without any outward sign. Grease every zerk after a wet trip and check the diff fluid; the intervals and the values are in your service manual.

The evergreen guidance on water crossings applies in full. Walk the crossing if you cannot see the bottom, know where your intake is, and do not follow a bigger vehicle through on the assumption that its line is yours. On a Sierra crossing in July, the water is cold enough that a stalled machine mid-stream is a problem for the occupants as well as the engine.