PORTLAND, Maine — Question: What's causing the massive California wildfires?
The wildfires have been relentless this month in California. As soon as conditions improve, they've gone downhill again.
Weather plays a big role in fanning the flames. The larger scale weather pattern across the western United States is responsible for what's known as the "Santa Ana" winds in southern California, and the "Diablo" winds in northern California.
This all starts when the jet stream digs down toward The Four Corners region. An area of low pressure - a storm - forms on the lee side of the Rocky Mountains, toward Denver. On the back side of the storm, pressure rises, and wind starts to pick up between high and low pressure.
As this high pressure zone becomes stronger, wind starts to blow toward lower pressure off the California coastline. This creates a broad flow of winds moving from east to west.
As this wind comes down off the mountains, it downslopes, or picks up speed.
It also dries the air out. Relative humidity has dropped to below 20 percent at times; in other words, the air becomes super dry.
Combine the super dry air with a gusty wind, and any fire that sparks up can spread. Sometimes the fires themselves even enhance the wind around them, and make matters only worse.
Have a weather or science question? See something in the sky recently that caught your eye? You ask... Ryan answers on the Morning Report. Send in your questions via Facebook, Twitter, or e-mail at ryan.breton@newscentermaine.com.