Dr. Cliff Mass
Many people died in the recent I-90 dust storm: Why it happened and how to prevent such tragedies.
On Friday night, around 4:30 p.m., strong winds preceded by strong thunderstorms pushed through central Montana, resulting in a local dust storm in which visibility dropped to near zero for several seconds.
As a result, at one location, (Hardin, Montana) a large pile of cars and trucks occurred, resulting in six deaths and many injuries.
Image courtesy of Jose Strickland
Such a large accident sequence during dust storms is not uncommon. For example, a few have happened in Arizona and eastern Oregon/Washington, such as a 38 car crash near Prosser, WA in October 2003 (my NW weather book participate in this and other events)
We understand the origins of such events, and as I will describe below, there are concrete steps, including new technology and meteorological guidance, that can hopefully reduce the frequency of coastal carnages. such road.
Friday’s event occurred on Interstate 90, just east of Hardin, Montana (red arrow on the map)
That afternoon, a powerful stream of thunderstorms formed on the eastern slopes of the Rockies and moved eastward into the plains. In fact, thunderstorms were forecasted hours in advance by the National Weather Service’s operational HRRR model (see the forecast of the simulated radar image for 4 p.m. Mountain Time). The National Weather Service has issued a thunderstorm warning for the time being.
Radar reflectivity forecast using HRRR model for 4pm Mountain Time
The actual radar image shows strong thunderstorm cells… .but more importantly… indicates a strong wind front pushed before the storm currents. Front gusts, which are related to strong wind acceleration and gusts, are generated by the cool air produced by thunderstorms (see figure below).
The gale front is usually visible in radar images because strong, cold currents on the gust front can push air upwards, creating clouds and some showers that can be detected by radar.
The National Weather Service radar image below shows the situation. The white star indicates the accident location and the white arrow shows the position of the front, rear gusts with gusts of 50-65 mph.
At 2036 UTC (2:36 MDT) – about two hours before the incident – you can see the line of thunderstorms and gusts ahead clearly represented by a thin line (see arrow).
At 4:20 MDT, just as the impact started, a strong gust of wind hit Hardin. Radar provides a lot of alerts!
The Weather Service’s radars are Doppler radars, which can observe wind as well as rainfall intensity (known as reflectivity). Below is an image of the Doppler wind at 3:58 pm. OH. You can clearly see ahead gusts with winds of 36-50 knots.
How strong is the wind blowing in and behind? Some surface stations have reported above 60 mph (see maximum winds for that day below)!
So why is there a dust storm? Because around I-90 there are plowed fields (see google ground image below at the accident site)
Winds of about 20-30 mph are very effective at removing dirt from exposed soil layers, found throughout the West due to large-scale agricultural activities in their area. ta. And arid farming areas (such as eastern WA and central/eastern Montana) are very susceptible to erosion as strong winds erode the soil.
Preventing Such Chain Accidents During Dust Storm
Most of these series of accidents happen the same way. People are driving fast and too close to each other. The lead vehicle in the convoy crashed into a reduced visibility area and braked sharply. And then other vehicles plow into that vehicle and each other.
So more responsible driving is definitely needed.
But there’s more than that. We may warn of such events. Not only is the forecast good for thunderstorms, but our surface observation stations and weather radar are also picking up HOURS winds before disaster strikes.
I repeat the HOUR BEFORE CLEARANCE.
Imagine if we created an environmental alert app that could be downloaded on everyone’s smartphone. Your phone will know a person’s location and warn you that strong winds are about to hit you — a clear warning of dust storms.
We can do this. And such an app can also warn about other conditions, such as ice on the road, flooding on the road and more. Call it “Driver Protection Application”.
I suggested to the Washington Department of Transportation that we create such an app for Washington State drivers, but they weren’t interested. Maybe someday someone else (maybe Google or Microsoft) might consider doing this. An app that continuously monitors environmental hazards in your location and gives you timely warnings. We can do it. Can save many lives.
Unbelievably, some in the media, coming to the world of journalism, declared that this terrible accident was a symptom of climate change.
Such claims have no basis in facts, science or anything else. The area of the dust storm does NOT fall under any type of drought (see below). And there is NO evidence of increasingly severe daily rainfall in the region over the past few decades, which could be a sign of global warming/climate change. I could say more about such journalism, but this is a family-friendly blog.
Outline area indicates the relevant Montana country.