Overview
Mid-March, Colorado experienced a major snowstorm that dropped 2 feet of snow and schools and offices were closed and traveling was discouraged. Northeastern Kansas had two EF-2 tornadoes that damaged trees and some buildings but no injuries. In late March, the region issued 9 total winter storm warnings before experiencing winter storm conditions and many states reported poor driving conditions and highway and interstate accidents and closures.
High winds and snow conditions were prevalent in early April in the region. In mid-April, Kansas experienced several tornadoes ranging from EF-0 to EF-2 while Nebraska received damage and power outages from severe storms. On April 26th, Nebraska issued 35 tornado warnings and experienced several tornadoes and damage from an EF-3 tornado around the Omaha area.
Wyoming and North Dakota experienced tornadoes, flooding, snow, and high winds in early May. Storms in late May had impacts across Colorado, Kansas, and Nebraska. Colorado reported hail with Yuma receiving enough baseball-sized hail it needed to be moved using heavy machinery and snow shovels. Kansas had two EF-1 tornadoes touch down in Johnson County. Nebraska experienced flooding in Wahoo and Leshara with evacuations being necessary in Leshara.
Severe Events
March
A powerful winter storm hit the Colorado Front Range on March 13th and 14th before ending the morning of the 15th. On Wednesday, March 13, precipitation started as snow in the mountains and foothills, but it started as rain across the I-25 Corridor and plains. Late evening of the 13th, the snow and rain mixed and created a heavy, wet snow across the Denver and Boulder metro areas, accumulating at a rate of 1 to 2 inches per hour. In the heaviest snowfall areas of Denver, snowfall amounts ranged from 14 to 22 inches. Areas along and east of a line from Fort Collins to Denver International Airport (DIA) remained mostly rain or rain snow mix until early morning Thursday, March 14th. The DIA received snowfall amounts of 5 to 10 inches. Locations farther east did not change over to snow until late on the 14th and received less total precipitation. Snowfall rates slowed during the morning of the 14th but increased again during the afternoon and evening before ending early morning of Friday, March 15th.
Shortly after the heavy snow on the 13th, difficult to impossible travel conditions started in the foothills. I-70 was closed, and dozens of vehicles became stuck and were abandoned. The depth of snow restricted travel to plowed roads as high clearance or four-wheel drive vehicles were unable to traverse unplowed roads. The weight of the snow snapped tree branches, and an estimated 113,000 people were without power during the storm. An estimated 800 flights were cancelled at the DIA, and there were widespread school closures on both the 14th and 15th from the Denver metro area to the foothills.
The storm did not take a typical track for producing heavy snowfall in northeast Colorado. Instead of developing in the Four Corners region and traveling eastward like typical storms, this storm was caused by a deep low-pressure center from south Idaho. The temperatures were cold enough, along with precipitation rates that developed due to a combination of moisture and instability, to turn the rain to snow over the Denver and Boulder metro areas. The liquid equivalent precipitation amounts were approximately 20% of the average annual precipitation occurred in the storm in and around the foothills. In areas to the east, the temperatures remained just warm enough to have a rain snow mix and received more than 2 inches of rain and snow liquid equivalent.
April
A tornado outbreak occurred across Nebraska during the afternoon and evening hours of Friday, April 26th. A vigorous low-pressure system moving through Nebraska that brought strong winds and cold temperatures over a warm, moist air mass created an environment for thunderstorms. The supercells that produced the tornadoes developed along a front that moved into eastern Nebraska from the west during the afternoon. 24 tornado tracks were counted for the National Weather Service (NWS) Omaha/Valley coverage area with five of them being rated EF-3. These are the strongest tornadoes in eastern Nebraska in nearly 10 years; in 2014, an EF-3 tornado occurred at Coleridge on June 17th, one day after four EF-4 tornadoes impacted northeast Nebraska.
The most damaging of these EF-3 tornadoes tore through Elkhorn and damaged Bennington and Blair. The 1-mile-wide tornado leveled houses in its path and left debris from the buildings it destroyed after it passed. In Douglas County, emergency officials announced 943 houses sustained some damage, and 173 of those are considered destroyed. Buildings that withstood the tornado were without power as the tornado tore down power lines. Omaha Rapid Response and the American Red Cross assisted with the clean-up of the damage and provide water and food to victims of the tornado. A federal emergency declaration was approved to provide relief to those suffering immediate and long-term effects of the tornado damage.
May
Yuma, Colorado suffered major hail damage from a hailstorm on the night of Monday, May 20th. Monday night’s storm brought heavy rain, high winds, baseball, and golf ball-sized hail. A tornado siren went off before the hail fell on the small town. The hail from the storm shattered vehicle windshields, pounded siding off buildings, broke windows, and killed livestock caught outside. The hailstones piled up on the streets, and the knee-deep piles of hail required heavy machinery and snow shovels to remove. Tuesday morning was focused on clean-up from the storm, and schools and district offices were closed due to a less severe storm on Tuesday night.