The global death toll from the coronavirus pandemic could triple by year’s end, with an additional 1.9 million deaths, while a fall wave of infections could drive fatalities in the United States to 410,000, according to a new forecast from the Institute for Health Metrics and Evaluation at the University of Washington.

This new estimate reinforces warnings by many experts that cooler, less humid weather, and increased time spent indoors, could lead to a surge in viral transmission — something typically seen with other respiratory viruses. Early on in the pandemic, the institute’s forecasts were influential in guiding policies developed by the White House coronavirus task force, but they have been criticized by some experts for making projections further into the future than can be done reliably.

The U.S. death toll from covid-19, the disease caused by the coronavirus, stands at 183,000, according to health data analyzed by The Washington Post.