Massive winter storms across the US forced COVID-19 vaccinations to grind to a halt in several states

• Extreme cold weather across much of the US has led to the temporary closings of vaccination sites.
• States including Texas, Missouri, and Alabama have paused vaccinations to keep people off the roads.
• In at least one case, vaccine supplies were put at risk when a backup generator failed.

The extreme weather and bitter cold battering much of the US have caused COVID-19 vaccination sites to close across the country and jeopardize vaccine supplies in some locations.

Missouri, Alabama, Kentucky, Indiana, and New Hampshire are among states that announced the temporary closing of health clinics and vaccination sites because of the weather.

In Detroit, more than 3,000 vaccine appointments were put on hold Sunday. The city is expecting 6 to 10 inches of snow; as of Monday night, a winter-storm warning remained in effect in the area.

On Monday, an organization that manages parts of the power grid in more than a dozen states from North Dakota to Texas ordered rolling blackouts to prevent uncontrolled power failures, leaving vaccine sites to rely on backup generators.

In at least one case, the backup generators failed.

Officials in Harris County, which includes Houston, scrambled to find recipients for more than 8,000 doses of the Moderna vaccine after a backup generator at the county's health department failed.

Health-department officials, concerned about people driving on the icy and snowy roads, worked to distribute more than 5,000 doses to local hospitals and health centers. About 3,000 doses were sent to the Harris County Jail, according to ABC News.

"There were already large numbers of people, where there were nurses, trained medical professionals, who could administer the vaccines and where wouldn't need people to drive somewhere in very dangerous weather and road conditions," Harris County Judge Lina Hidalgo told KHOU 11 of the decision.

Many vaccination sites across Texas say they'll remain closed through Wednesday in anticipation of further harsh winter weather. In some cases, vaccination sites will be closed until Saturday.

As of Monday night, more than 4.5 million people remained without power.

Some healthcare workers have already had to grapple with how to distribute vaccine doses in harsh weather.

In January, health workers in Oregon's Josephine County stuck on the highway in a snowstorm walked from car to car to administer doses of the vaccine before they expired. And clinics across the Northeast were forced to shut down in early February because of heavy snow.

About 38.3 million people in the US have received at least one dose of a coronavirus vaccine, according to the Centers for Disease Control and Prevention.