Glossary

Under normal atmospheric conditions, temperature decreases with altitude. The red line indicates the freezing level, where the temperature equals 0 C.

The freezing level is the altitude at which the air temperature reaches 0 C (zero degrees Celsius). In the atmosphere, temperature typically decreases with height so that the temperature is above 0 C at elevations below the freezing level, and below 0 C at elevations above the freezing level.

However, warm air associated with Pacific frontal systems frequently invades British Columbia during winter, causing warm air to overrun cold arctic air settled in the valley bottoms. This process creates a temperature inversion, where temperature increases with height, and can lead to an above freezing layer with multiple freezing levels.

Rising freezing levels are generally synonymous with rising temperatures and a sign of a warming snowpack.

Freezing Level