Ski resorts rely on snowmaking to get through winter. Climate change is making that harder.

A few days before Thanksgiving, Mark Nelson had hoped to be making snow at Bolton Valley Resort in northern Vermont. But instead, hoses hooked up to air compressors were just blowing air out over the icy ground to keep the system in working order in case temperatures dropped later in the day.

“We call it marginal when the conditions are like this,” Nelson, the independent ski area’s snowmaking supervisor said. “Marginal snow making.”

At 30 degrees Fahrenheit with high humidity, the afternoon was a bit too warm.