Most of the U.S. Is Experiencing Record-Low Drought Levels

Frederic J. Brown/AFP/Getty Images
Frederic J. Brown/AFP/Getty Images

This winter, relentlessly wet weather patterns bathed the United States with much-needed water. As a result, drought levels in the United States are at their lowest since Y2K, according to an analysis released by the United States Drought Monitor (USDM). Only 5.4 percent of the country is experiencing drought conditions right now, the lowest level on record since the USDM began a weekly analysis of abnormally dry conditions on January 4, 2000.

The USDM’s job is to measure the severity of a region’s dryness based on data like observed rainfall, soil moisture, streamflow, and water levels in lakes and reservoirs. This precipitation data is categorized on a five-point scale that ranges from “abnormal dryness,” the lowest category, to “exceptional drought”—reserved for the worst and longest-lasting drought conditions.

About 12 percent of the country is experiencing “abnormally dry” conditions, usually indicative of fleeting dryness that can often be remedied with a decent afternoon of soaking rain. The regions still thirsting for water are mostly in the southeastern United States, where widespread severe drought conditions persist over central and southern parts of Florida. The worst drought conditions exist there and over the mountains of northern Georgia, a tiny area that’s seen a rainfall deficit of 8 to 12 inches since last fall. But drought conditions across the rest of the country are largely scattered and limited in both scope and duration.

A major contributing factor to these delightfully low drought levels is California’s incredible reversal in fortunes this past winter. The state endured a devastating, years-long drought that abruptly came to an end after a steady train of storms rolled ashore and produced copious amounts of rain and snow. Much of central and northern parts of California have seen rainfall amounts of 1 to 2 feet above normal over the past six months. The Sierra Nevada mountain range in particular has seen more than 100 inches of snow this season, erasing previous years’ snowfall deficits and building up a significant reserve of meltwater to replenish downstream reservoirs when the warmth of summer takes hold.

Ironically, areas that were too dry not too long ago are now trying to cope with too much rainfall. North Carolina was hit especially hard toward the end of April, when a slow-moving storm system dropped more than 6 inches of rain across some of the most populated parts of the state. The heavy, steady rain mostly erased the state’s rainfall deficit in one weekend, but it also caused some major flooding problems. Raleigh, North Carolina, for example, found itself in a “flash flood emergency” on April 25, 2017, after excessive rains swelled local waterways beyond their banks and threatened homes, businesses, and major thoroughfares. When it comes to rain, as with everything in life, moderation is the goal.

What Is a Bomb Cyclone?

Maddie Meyer/Getty Images
Maddie Meyer/Getty Images

The phrase bomb cyclone has re-entered the news this week as parts of the central U.S. face severe weather. Mountain and Midwestern states, including Colorado, Nebraska, Wyoming, and South Dakota, all fall in the path of a winter storm expected to deliver tornadoes, hail, heavy snow, flooding, and hurricane-force winds on Wednesday, March 13 into Thursday. It seems appropriate for a storm that strong to have bomb in its name, but the word actually refers to a meteorological phenomenon and not the cyclone's explosive intensity.

According to The Denver Post, the bomb in bomb cyclone stands for bombogenesis. Bombogenesis occurs when a non-tropical storm experiences at least a 24 millibar (the unit used to measure barometric pressure) drop within 24 hours. Low pressure makes for intense storms, so a bomb cyclone is a system that's built up a significant amount strength in a short length of time.

This type of storm usually depends on the ocean or another large body of water for its power. During the winter, the relatively warm air coming off the ocean and the cold air above land can collide to create a sharp drop in atmospheric pressure. Also known as a winter hurricane, this effect has produced some of the worst snowstorms to ever hit the U.S.

The fact that this latest bomb cyclone has formed nowhere near the coast makes it even more remarkable. Rather, a warm, subtropical air mass and a cold, Arctic air mass crossed paths, creating the perfect conditions for a rare bombogenesis over the Rockies and Great Plains states.

Central U.S. residents in the bomb cyclone's path have taken great precautions ahead of the storm. Over 1000 flights have been canceled for Wednesday and schools throughout Colorado have closed.

[h/t The Denver Post]

Watch a Rare ‘Ice Tsunami’ Slam Lake Erie

Clean Lakes Alliance, Flickr // CC BY 2.0
Clean Lakes Alliance, Flickr // CC BY 2.0

A combination of freezing cold temperatures and high winds is creating an unusual phenomenon along Lake Erie. As KDKA reports, ice tsunamis are toppling onto lake shores, and many locals have been asked to stay inside and even evacuate their homes.

On February 24, 2019, the National Weather Service in Buffalo, New York issued a warning about dangerous wind gusts in the Lake Erie area. The service urged citizens to seek shelter indoors and avoid traveling if possible. Winds peaked at 74 mph earlier this week, the level of a Category 1 hurricane, and tore down trees and power lines throughout the region.

People who got close to Lake Erie during the windstorm witnessed a rare event known as an ice tsunami. When wind pushed ice on the lake's surface toward the retaining wall, the sheet broke apart and dumped massive ice chunks on the shore. The video below captures the phenomenon.

In some areas, the ice piles grew so large that roadways had to be closed. Residents of Hamburg, New York's Hoover Beach area were asked to voluntarily evacuate due to the encroaching ice.

Ice tsunamis, or ice shoves, are rare, but in some cases they can be life-threatening. In 2013, waves of ice shards from a Minnesota lake destroyed people's homes.

[h/t KDKA]

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