Wildfires that tore through Los Angeles early this year may have caused hundreds more deaths than official reports show, Boston University researchers suggest.

Wildfires that tore through Los Angeles early this year may have caused hundreds more deaths than official reports show, new research suggests. While the fires were said to have taken 31 lives, a study published Wednesday in the Journal of the American Medical Association estimates that about 440 more deaths may be linked to the disaster.

Rising temperatures pose new challenges for firefighters who have made incremental progress against a massive wildfire in central California that has injured four people as it has become the biggest blaze in the state so far this year.

The Gifford Fire, a wildfire burning in Central California that has destroyed over 83,000 acres in six days, continues to rage and is now the largest blaze in the state this year, according to Cal Fire.

As Canada grapples with one of its worst wildfire seasons on record, smoke from the blazes have prompted air quality alerts across the U.S.

Smoke from fires across the West and Canada is causing potential health risks for people across the U.S. Satellite images show smoke from the wildfires in California is creating unhealthy air as far away as Las Vegas.