If current trends hold, short-term forecasts predict hospitalizations to go up 89% in the next month, Ghaly said.
California currently has 2,578 people hospitalized with COVID-19. That number could rise to 4,864 by Oct. 25, Ghaly warned.
MAP: CA counties that can, can't reopen under new rules
We may be starting to see the effects of Labor Day socializing, which was two and a half weeks ago. Increased transmission may also be a result of more reopening allowed by California's switch to a four-tier reopening plan three and a half weeks ago.
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"With reopening we know that there's more opportunities for mixing and exposure to others that we're not frequently around," said Ghaly. "We've seen that before and we've done a good job to bring it down.
"It's really about not letting our guard down as we did earlier in the summer."
WATCH | Here's a breakdown of each tier in Newsom's reopening framework