California, with its sun, beaches along the Pacific Ocean coast, and temperatures soaring to 40 degrees Celsius in March. This state, along with several others in the western United States, is entering a historic heatwave this week with unprecedented levels never seen before at this time of year. Temperatures have already started to rise significantly and will reach notable levels starting from Wednesday.
As noted by the specialized site Extrême Météo, this event will be reminiscent of a previous heatwave that occurred in 2021, but it more logically took place in June. With temperatures regularly above 30 degrees Celsius and reaching 40 degrees Celsius in several places, François Jobard, a meteorologist with Météo France, describes the situation as “insane”. On the social network Bluesky, he cites the example of Phoenix, Arizona, where “the official forecast indicates that we could break the previous heat record for April (41 degrees Celsius)… just before the spring equinox.”
Tens of millions of people exposed
The meteorological chain explains the origin of this exceptional heat. “This remarkable weather situation is explained by the establishment of a heat dome over the American West. This phenomenon corresponds to an area of very persistent high pressure that acts as a lid in the atmosphere. The warm air is then trapped near the ground and gradually warms up day by day under the effect of sunlight.” California, Arizona, Nevada, and New Mexico are the most exposed areas; Utah, Colorado, and Oregon could also be affected, as shown on a map provided by Météo Express.
The National Weather Service (NWS), the American equivalent of Météo France, estimates that maximum temperatures will be up to fifteen degrees above seasonal averages. This organization also points out that this situation is more typical of early June weather.
The NWS is issuing a warning to vulnerable individuals such as young children, the elderly, pregnant women, and the sick. Tens of millions of Americans will be exposed to these very high temperatures. It is recommended to limit intense activities and stay hydrated. It is also important not to leave anyone in a closed vehicle.
An episode that could last ten days
In Los Angeles, for example, temperatures are expected to peak between Wednesday and Thursday with highs ranging from 32 to 37 degrees Celsius, as reported by NBC. Moving further inland to Palm Springs, temperatures near 40 degrees Celsius are expected from Wednesday to Friday at least. Currently, forecasts suggest a heatwave that could last for about ten days.
This situation follows a remarkable fall and winter. Even though parts of the country experienced significant snowfalls and temperatures below -20 degrees Celsius, overall the period was remarkably warm. François Jobard highlights that “the September to February semester is the warmest ever recorded in the United States.”
