Hot and sunny weather in Arizona led to crowds tubing on at least one river this weekend as that state and a dozen others face the worst surge in coronavirus cases since the pandemic started.

Temperatures were expected to rise to over 100 Fahrenheit (38 Celsius) on Sunday along the Salt River east of Phoenix. On Saturday, dozens of people climbed into inflatable inner tubes with coolers and took to the water to escape the heat. Very few wore masks.

Texas shuttered tubing and rafting business on Friday and some beaches in Florida are closing again ahead of next weekend’s Fourth of July holiday to try to curb the rising outbreak in those states.

The surge in COVID-19 cases has been most pronounced in a handful of Southern and Western states that reopened earlier and more aggressively, despite warnings by health officials to wait to see a steady decline in cases.

For a third consecutive day on Saturday, the number of confirmed US cases rose by more than 40 000, one of the largest surges in the world. In Arizona, cases have risen by 267% so far in June and jumped by a record 3 857 cases on Sunday, the eighth record-breaking increase this month.

Even in states where cases have been declining for weeks, outbreaks are happening. One bar in East Lansing, Michigan has been linked to more than 76 cases, according to the Ingham County Health Department. That number is likely to rise, officials cautioned.

Just a day after he sounded a note of optimism about the US response to the pandemic and said the country was in “a much better place,” Vice President Mike Pence canceled events to campaign for Republican President Donald Trump’s re-election in Florida and Arizona due to the outbreak, campaign officials said on Saturday.

In an interview with CBS, Pence said he was confident that there were enough health care supplies and capacity to deal with the spike in cases.

He also defended Trump’s refusal to directly ask Americans to wear masks or to wear one in public himself, even as Texas Governor Greg Abbott and others say the widespread use of masks will be critical to be able to reopen the economy.

“We believe people should wear masks wherever social distancing is not possible, wherever it’s indicated by either state or local authorities,” Pence told CBS.

US House Speaker Nancy Pelosi, a Democrat, has criticized the administration’s response to the pandemic that has killed more than 125 000 Americans. She told ABC News on Sunday that mandating the use of masks across the country was long overdue.

Global coronavirus cases exceeded 10 million on Sunday according to a Reuters tally, marking a major milestone in the spread of the respiratory disease that has so far killed almost half a million people in seven months.