On Saturday when I went skiing it was just above freezing at my house and you could not see 100 yards. Even the Pyramid parking lot was socked in. But when I climbed up the mountain at just about 1200 feet it cleared off and got warm. The higher I went the warmer it got, and the softer the snow.
Since it had been freezing overnight at my house I expected ice on high. I was shocked to find spring skiing conditions and tee shirt weather. This is a classic example of a temperature inversion. Cold and foggy in the valley and warm and sunny on high. Overnight it was warmer on Pyramid than it was at my house by the sea.
When I skied down I went into the fog and it was like skiing into a wall of cold air. And the snow got icy!