In Arizona, public health officials warn extreme heat in Maricopa County has led to the suspected deaths of over 400 people so far this summer. August is on track to be Phoenix’s hottest on record, with temperatures reaching at least 110 degrees Fahrenheit every day this month except one.

In Alaska, a lake of rainwater and melted snow burst a glacial dam north of Juneau on Wednesday, causing the Mendenhall River to swell to a record height, flooding homes and streets in Alaska’s capital city. Mountain glaciers worldwide are shrinking at a record pace as global temperatures continue to rise due to greenhouse gas emissions.