(CNN) — Wildfires are expected to bring unhealthy air to more than 120 million people this weekend, but the smoke and its toxic particles may not always be clearly visible. Some skylines are shrouded ...

(CNN) — Thick, choking plumes of smoke from wildfires in Canada are pouring into major cities across the Midwest, Northeast and mid-Atlantic, bringing dangerous air quality to more than 100 million ...

(CNN) — Drenching storms rolled over the flood-ravaged Midwest for a sixth day early Friday, bringing more rain to areas where severe flooding has already forced hundreds of people from their homes ...

(CNN) — The US has experienced a spate of flash flood emergencies during the past two weeks, illustrating July’s dangerous side. The month has featured multiple 1,000-year rainfall events across the ...