An unprecedented ‘heat dome’ is hovering over Texas, setting record high temperatures (up to 125ºF), imposing dangerously high heat indexes, and threatening an overstretched power grid. The heat dome is an atmospheric condition resulting from the interaction between high- and low-pressure systems, amid anomalous jet stream patterns.

The heat dome is happening in part because of an unprecedented fragmentation of multiple jet stream currents. Global heating and climate disruption have created these conditions, and so Texans are now experiencing three weeks of heat indices above 100ºF, and all-time record demand on power production.

The National Weather Service is confirming three consecutive weeks of heat index values of 100ºF or above in Houston and other parts of Texas. Image: NWS Houston.

Jet streams are major planetary wind currents that define climatic regions and shape what kind of weather and ecology a given region experiences. They tend to balance out over time and show fairly consistent behavior. The Polar Vortex, for instance, normally circles the Arctic; when temperatures in the Arctic warm too much, the difference from lower latitudes is blurred, and the polar jet stream bleeds to lower latitudes.

Texas has been particularly hard hit by polar weather it was unprepared for. The result was collapsing power and heating systems, devastation to local economies, and a tragic number of preventable deaths. Market prices for energy and especially heating spiked across the country as Texas sought to import enough gas to cover demand. People ended up paying egregiously inflated prices for little to no delivery of service.

The heat dome is not only historic and hovering over Texas; it is now spreading to much of the southern United States and Mexico. The Guardian is reporting:

The National Integrated Heat Health Information System (NIHHIS) said more than 46 million people from west Texas and south-eastern New Mexico to the western Florida Panhandle were under heat alerts. The NIHHIS is a joint project of the federal Centers for Disease Control and Prevention and the National Oceanic and Atmospheric Administration (Noaa).

By July 4, it is expected some parts of Texas will have experienced three consecutive weeks of heat index values of 105ºF or higher. In some cases, this means everyday activity cannot go on as usual. Local communities are facing severe impacts from rising health risks. Some days have seen hundreds of people rushing to emergency rooms with heat-related illnesses.

Even as Texas communities grapple with unrelenting extreme heat, the state has passed a law to nullify and prohibit local rules requiring water breaks for outdoor workers. according to the Texas Tribune:

Texas is the state where the most workers die from high temperatures, government data shows. At least 42 workers died in Texas between 2011 and 2021 from environmental heat exposure, according to the U.S. Bureau of Labor Statistics. Workers’ unions claim this data doesn’t fully reflect the magnitude of the problem because heat-related deaths are often recorded under a different primary cause of injury.

NBC News is reporting:

Over the past week, several cities in Texas, including San Angelo and Del Rio, have hit or surpassed 110 degrees Fahrenheit — temperatures that are more common at this time of year in parts of northern Africa and the Middle East.

While the unremitting heat dome is creating unlivable conditions for many in Texas, clean solar and wind energy have been critical for avoiding blackouts, which could be deadly.