PROVO — By now, most Utahns know that Thursday's odd freezing rain was a major rarity for Utah. But new research by a BYU professor shows why some weather can be tough to predict, even for the best professional forecasters.
On Thursday, BYU elementary education major Jessica Reynolds didn’t make it 100 yards from her car before she took a spill, cutting her hand and twisting her ankle.
She was far from the only casualty as the ice spread across northern Utah, unanticipated by nearly everyone.
BYU mechanical engineering professor Julie Crockett has an explanation for why it is not uncommon for weather reports to make mistakes. Her research may even help forecasters improve their predictions.
Crockett’s studies, recently published in the “International Journal of Geophysics,” focus on atmospheric waves, enormous waves inside of storms that can be miles high and wide. These waves can amplify, disrupt or disperse weather patterns and, because they are not visible, their presence and effects are hard to detect and anticipate.
They add unpredictability to weather forecasting. Think of airplane turbulence.
“What my research does is actually try to understand these waves interacting with other waves or winds going on so you can actually, in a model, predict what these waves are going to do,” Crockett said.
The waves are everywhere and caused by factors like wind moving over mountains, different temperatures and changing densities in the air.
“Because of this energy associated with them,” she said, “they can actually run into something like a storm or other currents or winds and either enhance that by giving energy to (it), the energy they have just oscillating back and forth as waves; they can amplify something like a storm or winds; or they can actually do the opposite and cause it to decrease because they can take energy, basically, from the storm. Or they can break, the same way waves break when they reach the beach. If these waves hit another wave or hit something else, they can break as well.”
When these waves are better understood and more foreseeable, perhaps weather events will be easier to catch ahead of time — before the unsuspecting find themselves face up on an icy sidewalk.
The unexpected blanket of ice is a rare weather event in this area. Kevin Eubank, chief meteorologist for KSL weather, said the northeastern parts of the United States are familiar with freezing rain, but as far as he can remember it hasn’t happened here.
“No one in this market before has probably forecasted freezing rain for the morning commute. … That’s like forecasting an avalanche.”
Eubank said the freezing rain was a result of the inversion.
“In an inversion, we get cold air that gets trapped down in the very low levels of the valley floors and then warm air aloft,” he said. “So the storm that came in the other day wasn’t a big storm at all; it was very, very small in scale. But because it was warm up above, it fell in the form of rain. … The minute that water hit those surfaces, it froze and it glazed everything over.”
A stronger storm must come through to break up the inversion and get the temperatures above freezing, otherwise Eubank said the ice will continue to melt a little during the day and freeze again at night.
Whether that storm happens soon or not, hopefully the BYU grounds crew can keep up with the freeze-over to avoid anything like Thursday’s freezing rain. Northeasterners may be experts at navigating their way around a regional ice rink, but those in Utah don’t have the same experience. Reynolds said the trek across campus was treacherous for everyone.
“I got up to the (Richards Building) stairs, and I saw two people slip on the stairs and start sliding down,” Reynolds said. “They only stopped when people they were sliding past, like, grabbed their backpacks or their coats and stopped them.”