This Sunday, Death Valley hit a new all-time June record high temperature of 129 degrees Fahrenheit. It was the most recent high mark in a record-shattering heat-wave that baked the western US over the weekend, pushed power grids to the limits, resulted in numerous heat injuries and one death, and sparked multiple dangerous and deadly wildfires.
Though the forecast is for high temperatures to slightly abate over the coming days, the long-range outlook is for heat to return with a vengeance by about July 11th. Overall, temperatures are expected to drop from the 110s and 120s into the still excessive, 100s and 110s, then jump back toward record-setting levels.
A large, high amplitude blocking pattern and associated heat dome high pressure system is expected to persist. So conditions remain for temperature spikes as July progresses. With no long-range changes in this Jet Stream configuration expected, the Southwest will stay under the gun for record heat and dryness probably at least until the end of summer. So this initial volley of record heat can best be described as the first in a very vicious pattern of heat pulses which are likely to continue through the hot months of July, August and September.
This extreme Jet Stream induced hot pattern is plainly visible in the latest ECMWF model runs.
(Image source: ECMWF)
Here we see the record heat predicted for tomorrow with a broad area of 95 degree average 5,000 foot temperatures expected. Average temperatures of 95 degrees at the 5,000 foot level can often result in 110 or greater daytime high temperatures at the surface. As noted above, these very hot temperatures are expected to fade somewhat over the coming week before rising again toward record highs by around July 11th.
More than 20 Large and Dangerous Fires Ignite in US Southwest
This heat wave is just the crowning blow in a long string of warm, dry weather that has settled over the US Southwest since early 2012. The extraordinarily long duration heat and drought is the direct result of a near-permanent blocking pattern. A high amplitude wave in the Jet Stream and associated blocking high pressure have kept heat and drought conditions continuously in place. Such a stationary pattern is not normal and is brought about by a loss of sea ice and snow cover over the Arctic which is a direct result of human-caused climate change. These changes have both slowed down the Jet Stream and made weather patterns more persistent. Beneath the up-slope of these large blocking patterns heat waves, droughts and fires become a near-constant hazard. In the troughs, cooler and much stormier conditions predominate.
In the west, fears were that, eventually, massive and damaging wildfires would result from the epic heat and drought. At first, it appeared that Colorado would be ground zero for this year’s fire season. There, multiple blazes devoured tens of thousands of acres and hundreds of homes. A single devastating fire, the Black Forest Fire, destroyed about 500 homes. Now, the current heatwave has set off numerous large blazes. Over the weekend and into Monday more than 20 massive fires sprang up throughout this drought and heat stricken region.
As the worst of these fires bore down on Yarnell, Arizona, a team of 19 firefighters lost their lives while attempting to defend the town from the rapidly spreading blaze. A quick shift in the wind forced the firefighters to resort to the use of emergency shelters as the flames turned toward them. Sadly, only one of the team survived. The blaze quickly engulfed the town, destroying at least half of the 700 buildings there.
Dangerous fires also raged in California, Nevada, New Mexico, Utah and Colorado. Unfortunately this might be the beginning of a very long, dangerous, and costly fire season. Jason Sibold, an ecologist at Colorado State University reported to Business Journal:
“That area is experiencing extreme drought, low snowpack, late onset of winter, early snowmelt and warmer springs and summers. A lot of those places, in the old climate scenario, would still be under snow. There’s no way they would be burning.”
So the long period of heat, drought and ever-expanding wildfires for the US Southwest, predicted by climate scientists and brought about by human caused global warming, appears to have started. Unfortunately, it only gets worse from here. Even with very aggressive reductions in greenhouse gas emissions, conditions will continue to worsen over the next few decades. Without a rapid reduction in greenhouse gas emissions, the drought which is now devastating the US Southwest will steadily expand north and eastwards until almost half of the United States is impacted. In Europe, the Sahara Desert eventually jumps into Spain, Italy, Greece and southern France and Germany.
An expanding band of heat-bleached and eventually uninhabitable lands eventually engulf the equatorial regions and grow polewards. If we wish to slow and then stop the growth of these damaged zones, then we must stop emitting carbon into the atmosphere as soon as possible.
Sadly, the most recent droughts, heatwaves, and wildfires in the US Southwest are just some of the milder first assaults of global warming. Things get worse from here. Far worse if we don’t drastically reduce carbon emissions.