Based on the weather in Bishop, California, United States Of America as of February 12, 2016 10:42pm local time

Why? Because it's cold. simple as that.
Current Conditions
Partly Cloudy
Temp: 41°F5°C
Wind: 3.5 MPH5.6 KPH
Precipitation: None

Next 2 hours: Yes

Next 4 hours: Yes

Next 8 hours: Yes