A wide area around the Four Corners region of the U.S. Southwest is now in severe drought — and the three-month outlook is grim
When it comes to snow cover, a comparison of satellite images shows just how much a difference a year can make. (Images: NASA Worldview. Animation: Tom Yulsman) While downtown Boston streets were flooding and then freezing as a result of the powerful bomb cyclone that pummeled the U.S. East Cost, folks in the U.S. Southwest were no doubt wondering when they might get even just a little taste of winter. From October 1 to January 5, an almost non-existent 0.01 inches of precipitation was recorded in Flagstaff, Arizona, according to an update from the National Oceanic and Atmospheric Administration. The September 1 through Christmas period was the driest on record. Flagstaff is no fluke. From NOAA's update:
A wide area around the Four Corners region of the southwestern United States is currently in a severe drought according to the January 2 United States Drought Monitor. An even broader area, including Arizona, most of Utah and parts of Colorado and New Mexico, is currently experiencing moderate drought.
With so little precipitation falling on the Southwest, snow cover in the region is very thin. The animation above offers a dramatic visual sense of that. It consists of two images acquired by NASA's Terra satellite almost exactly a year apart. The first was acquired on January 6, 2017. Much of the region is obviously covered in snow. The second was captured on January 4, 2018. There's some snow in the mountains of Colorado at upper right. Otherwise, nada. To get your geographic bearings, look toward the upper right quadrant of the imagery. The two lines that cross there mark the borders between the Four Corners states. Clockwise from upper right, these are: Colorado, New Mexico, Arizona and Utah. (Where the lines intersect marks the actual Four Corners, where all four states come together.) On the left hand side of the imagery, half way between the top and bottom, look for the big gash in the crust of the Earth. This is the Grand Canyon. The North Rim of the Grand Canyon is at an elevation of more than 8,000 feet. So it can get very snowy there — as is evident from the 2017 image. In fact, the average annual snowfall there is more than 10 feet! (134 inches, to be exact.) But so far this cold season, through Dec. 31st? Zilch. The North Rim had received not a drop of moisture since September 15.
A comparison of drought conditions between early January of 2017 and 2018. The two maps above show how drought conditions in the entire Western United States have changed over the course of a year. The most obvious — and welcome — change is the dramatic shift in California. Even so, a large swath of moderate drought persists in Southern California. Given the intensity of the Thomas Fire and others in the area, this remains very concerning. Now shift your attention over to the Southwest and the For Corners area specifically. Check out that T-shaped area of severe drought that has appeared since last year at this time. If the region doesn't get some relief soon, we should start seeing some alarming red colors there in the coming weeks. And unfortunately, in part because of the weather-influencing La Niña phenomenon in the equatorial Pacific, the outlook is for warm, dry conditions to continue for awhile.