Amid rising coronavirus cases in Colorado, as many as 15 counties are at risk of losing existing variances to Gov. Jared Polis’ public health order.

Jill Hunsaker Ryan, executive director of the Colorado Department of Public Health and Environment, announced that 15 counties in Colorado have been notified that the rate of increase of cases exceeds a state “early warning system” of metrics.

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Those counties could lose state-granted variances that allowed more relaxing of public health orders around the number of people who can be at a gathering, for example. Of the 15, eight have decided to voluntarily go back to the previous phase, known as “Safer At Home,” which requires more telecommuting and limits gathering to 10 people or fewer. Those that don’t voluntarily go back have two weeks to reverse the trend of increased cases, Ryan explained. If they don’t reverse the trend, the variances will be revoked.

RELATED: Polis makes “last call” for alcohol much earlier in Colorado

The number of new cases in Colorado has doubled in recent weeks, from 200 per day to between 400 and 500 per day. “We can’t afford another doubling” in cases, Polis said Tuesday.

The metric Ryan pointed to is a county with more than 100 cases per 100,000 population. That puts the county in the red zone, she said.

The counties notified that they needed mitigation plans or go back to Safer at Home: Adams, Arapahoe, Broomfield, Chaffee, Custer, Denver, Douglas, Eagle, El Paso, Garfield, Grand, Larimer, Mineral, Pitkin and Prowers counties. Ryan said the eight that voluntarily went back one phase were the smaller ones, which could include those outside the Front Range: Chaffee, Custer, Eagle, Garfield, Grand, Mineral, Pitkin and Prowers.

What’s at stake is economic stability, Ryan said. “If we can control [the virus] at the county level, it reduces the need for a statewide disruption. Getting children back into the classroom also is at stake, she said, as well as overwhelming hospital systems.

Polis said his next briefing on Thursday will be on the situation around testing. The state is collecting thousands of samples per day but complaints are rising on the turnaround for test results, as much as 14 days.

Polis also announced during the Tuesday news conference that the last call for alcohol at restaurants and bars that have converted to restaurants is being shortened from 2 a.m. to 10 p.m. by executive order. Read more here.