EXPLAINER: What's Behind The Heat Wave In The American West?

Much of the American West has been blasted with sweltering heat this week as a high pressure dome combines with the worst drought in modern history to launch temperatures into the triple digits.

Record daily highs have been seen this week in parts of Arizona, California, New Mexico, Utah, Montana, Wyoming and Utah even before the official start of summer. Phoenix is baking in some of the U.S. West’s hottest weather and hit a record-breaking 118 degrees Thursday. Climate scientists say the early arrival and intensity of the heat wave have much to do with a long-running drought gripping the region and climate change.