#1 Couloir is the first major couloir on the left of Harwood's north face, if viewing it from the north like a book. It starts close to Stockton Flats and continues up in a simple straight line to the top of Harwood.
Careful study of maps of the area is one's best bet to find the base of the route. Routefinding is not challenging on the route, but the mouth of the canyon leading to it can be tricky sometimes. Intimate familiarity with the Stockton Flats area is a plus.
Route starts up easy snow, moves through your choice of three constrictions/smaller gullies, and then continues up to the summit in a straight shot. The rightmost gully is preferred, as it offers the cleanest line. However, in spring, or in low snow conditions, the left two gullies hold snow longer. If you ascend one of the gullies on the left, you'll need to traverse west to gain the primary gully. The rest is a straight shot.
As always, a helmet. Crampons and a single axe are necessary, though you have leeway in your choice of crampons/boots/axe. It's not a demanding route, as it's similar to doing part of Snow Creek on San Jacinto. I would advise against soft-soled trail runners with strap crampons if the conditions are going to be hard-packed and icy.
Trip Report with Lilbitmo and Sam Page
Trip Report on The Mountaineering Review