HOLDERNESS, N.H. — It’s cold enough for annual tradition of harvesting lake ice at a New Hampshire campground.

Crews started sawing blocks for the Rockywold-Deephaven Camps in Holderness on Tuesday. The event goes back a century.

It’s a timely start, helped by very low temperatures. In 2013, the three-day harvest at Squam Lake didn’t start until Feb. 6 because of rain, warm temperatures and wind.

Instead of refrigeration units, campers use lake ice packed into insulated ice houses that keep the blocks frozen through summer. The 16-by-19-inch ice blocks weigh between 120 and 160 pounds each.