Road crews are expected to start chewing into the deep snow on State Route 410 next month with the goal of readying Chinook Pass in time for the traditional Memorial Day weekend opening.

Work on the 5,430-foot mountain pass west of Yakima is expected to begin the second week of April.

Snow depth at Chinook Pass averages about 18 feet before that work starts, said state Department of Transportation spokeswoman Summer Derrey. Thus, snow removal and avalanche control are a significant, multiweek undertaking, she said.

Farther to the north, efforts to reopen the North Cascades Highway — which tops out at 5,477 feet — usually begin around the first day of spring, which is March 20. But this year, transportation officials are optimistic that State Route 20 could be open before the first of May, which hasn’t happened since 2010.

Earlier this week, DOT avalanche-control specialists Mike Stanford and Harlan Sheppard ventured up and over the North Cascades on snowmobiles from the Early Winters information center to Rainy Pass. Along the way, they stopped to measure snow depths at more than two dozen avalanche chutes and other sites.

“There’s still more winter coming — I expect we’ll have more snow by the end of March,” said Stanford. “But we found much less than we had at this time the past two years — and at some locations, almost half as much.”

The earliest Chinook Pass opened was in 1973, when it was cleared by April 5. The latest opening came the next year, when it was closed until July 12.

Nearby Cayuse Pass, which is also on State Route 410, should open around the same time as Chinook, she said. Snow depth there is about 12 feet.