Jun 15, 2016
California Heat Waves – A New Type of Heat Wave
by
,
California-Nevada Climate Applications Program – A NOAA Risa
- Reviews existing literature on heat trends in California
- Finds the traditional type of heat wave, natural for California's semi-arid Mediterranean climate, has increasingly tended to be more humid and more often accentuated at night since the 1980s
- States humidity leads to higher night time temperatures and also makes extreme heat much more difficult for humans as it reduces our bodies’ ability to cool off by evaporating water – sweating
- States the observed trend towards more humid, more intense and longer-lasting heat waves in California has so far culminated in the July 2006 heat wave, an event of unprecedented impact on human health in the state
- States that heat waves impacting California are caused by a specific weather pattern characterized by high atmospheric pressure in the Great Plains and low pressure off California’s coast which together draw warm moist air from the south
- States that coastal waters west of Baja California are an important source for this humid air; these waters have become unusually warm in recent decades as part of a global warming pattern and have been partially responsible for the fact that the rare weather patterns associated with great California heat waves have tended to bring warmer, more humid air