Category: Met 101/Weather History
On the morning of Thursday, June 7, 1984, weather maps showed a major trough of low pressure across the western United States, anchored by an upper low over the northern Rockies. A long cold front snaked from Canada down through the Upper Midwest into the Plains. An occluded low pressure system was over southern Canada. A new low pressure system had formed to the south and was moving northeast off the plains of eastern Colorado. A strong complex of thunderstorms had moved through the Upper Midwest during the early morning hours, but across the region, the atmosphere reloaded quickly. Dewpoints were in the middle and upper 60s
By afternoon, an explosive situation was in place with high instabilities and increasing wind shear as the low pressure system intensified while moving toward the Upper Midwest. Thunderstorms broke out during the afternoon from Minnesota into Iowa. Tornado reports started to come in by mid-afternoon, where a rash of at least fourteen tornadoes plagued the northwestern part of the state.
Further south, other tornadoes touched down in Missouri. One family of tornadoes started near the Missouri/Iowa border. This supercell storm produced at least four tornadoes along a 140 mile path across much of Iowa. Three tornadoes were rated as F3s and one was rated F4 out of the afternoon activity. The F4 tore through the town of Wright, Iowa, killing two. The tiny town was completely leveled, with all 25 homes destroyed and all but two buildings destroyed. In addition, one person died near Ringgold, Iowa and three more in Harrison County, Missouri.
But the deadliest tornado of the outbreak would come during the early morning hours of June 8th. The complex of storms that had produced the long-track tornadoes in Iowa weakened during the evening hours. But as it moved toward southwestern Wisconsin, it encountered a higher level of instability and shear and the storms began to strengthen. A tornado watch was issued at 11 p.m. The first tornado touched down around 12:30 a.m., remaining on the ground for several minutes. A more powerful tornado touched down near Mineral Point. A few miles to the northeast, many of the 582 residents in the town of Barneveld were awakened by a massive clap of thunder right before the power went out. The town’s tornado sirens remained silent due to the power outage even as the huge F5 tornado roared toward Barneveld.
As the tornado ripped through Barneveld, it was at least 400 yards wide. When it finished its destructive rampage, 90% of the town lay in ruins. Seventeen of eighteen businesses were destroyed, as well as the municipal building, bank, post office, fire station and three churches. A total of 93 homes were destroyed and another 64 heavily damaged.
A total of nine people lost their lives in the inky blackness that night, while 200 were injured. The town’s water tower was damaged, but was the only thing left standing amidst the tremendous devastation.
For years, residents of the tiny town spent many a sleepless night listening to every rustle of the wind for the sound of another deadly nighttime visitor.
As German soldiers peered out from their bunkers along the French coast on the morning of June 5, 1944, they knew there was no way that the long awaited invasion by the Allies was coming that day. High winds, heavy rains and huge waves were pounding the beaches all along the English Channel that day. June 5th had been the day that the invasion was scheduled to launch. But Allied weather forecasters had accurately predicted the terrible weather that occurred. If June 5th had been D-Day, the results would have been terrible.
So the forecast had been accurate, staving off a disaster, but Allied commanders were nervous. The landings depended on a complex set of factors, including tides and moonlight and other things. The early June window for invasion was about to close and would not reopen for two weeks. The element of surprise was a huge factor, and waiting an two additional weeks would reduce the Allies chance of success. So as you can see, weather was critical in the decision making process.
In April 1944, a joint Allied team of British and American forecasters had been established to create five day forecasts for commanders. A five day forecast was something that was unheard of at that time. Their first job was to pick a time that climatologically would be favorable for the invasion. They chose early June. June 5th would be the day. But weather maps on June 3rd and 4th showed a depressing situation for forecasters and military leaders. Several low pressure systems were poised to move across the invasion area over the next several days.
Allied forecasters had an advantage since their forces controlled most of the North Atlantic and weather data was more plentiful to them than to the Germans. This data revealed a small window of better weather that would occur on Tuesday, June 6th as a small ridge moved over the area between two low pressure troughs. The decision was made to go then.
Allied Forces landed on the beaches of Normandy on the morning of June 6th, 1944,, opening the long-awaited second front against the Germans and spelling the beginning of the end of World War II. The Germans were completely caught by surprise. Their military leaders believed that the Allies would wait until there six good days of weather before crossing the channel. At the end of the first day, the Allies had suffered 12,000 casualties. Commanders had expected as many as 75,000.
Weather forecasting had played an important role in the success of the operation, but a closer look reveals that the German forecast was actually better than the Allied forecast. The German predictions were actually closer to the actual wave heights, which were critical to the success of conveying men and materiel to the beaches on landing craft. The German forecast led them to them being relatively unprepared with their commander Irwin Rommel away from the field. The wave heights were actually above the critical threshold set by the Allies for invasion. If their forecast had been more correct, they might not have made the fortuitous decision to launch on June 6th.
It really makes you stop to consider the relationship between accuracy and value in a forecast and how it is interpreted by its end users. Dr. Harold Brooks eloquently discussed this in episode 322 of WeatherBrains on June 4, 2012. Listen to the podcast.
A final note: if the invasion had not occurred on the 6th, the next window of opportunity standpoint would have been the 17th through the 21st. A storm of historic proportions during that time could have proven disastrous for the invading forces.
The 305 foot tall Teton Dam designed to provide tremendous benefit to the farmers and residents of the Snake River area of Idaho. Built by the U.S. Bureau of Reclamation, it was supposed to eliminate the threat of spring floaods and provide year-round water for irrigation.
The earthen dam had just been completed in June of 1976, and men and equipment were still on-site. But the dam was defective.
Runoff from heavy snows during the winter had filled the reservoir behind the dam to capacity. Water began leaking from the dam on June 3rd, but there seemed to be no cause for alarm.
By 9:30 a.m. on Saturday morning June 5th, new leaks were spotted and bulldozers were used to try and shore up the dam. By 10:30 a.m., warnings were frantic as officials warned residents below the dam that it was about to break. Around 11 a.m., a whirlpool appeared as water was pouring through the earthen dam. The hole in the dam enlarged to 25 feet in diameter, nearly swallowing a bulldozer working to plug the hole. Shortly after that, the western side of the dam seemed to crumble.
Over 180 billion gallons of water were soon pouring down the Teton River Canyon. The towns of Wilford, Sugar City and Rexburg were inundated. Damages totaled $400 million. Eleven people lost their lives along with 13,000 head of cattle.
Had the disaster occurred during the nighttime hours, the death toll would likely have been in the thousands as sleeping residents would not have had time to hear the warnings to evacuate.
The El Reno, Oklahoma Tornado occurred on this date two years ago. It was a game changer for storm chasers.
The event had been well forecast. Hundreds of chasers had converged on the small community in Canadian County, Oklahoma. A thunderstorm developed in the explosively unstable environment, going from relatively harmless cumulus clouds to a powerful supercell thunderstorm extending more than 60,000 feet into the atmosphere.
The tornado touched down at 6:03 p.m. about 8 miles west southwest of El Reno and lumbered slowly southeast. Almost immediately, it was already a wedge, the visible funnel beneath the cloud base wider than it was tall.
Researcher and storm chaser Tim Samaras, his son Paul and Carl Young were monitoring the storm from a position about 2.5 miles to its northeast. By 6:09, the tornado was already rain wrapped, obscuring its true intentions from chasers. It was accelerating and turning east just south of Reno Road approaching Brandley Road. Samaras and his team were struggling to get ahead of the fast moving tornado as they navigating, south, then east and then north, just out of the tornado’s reach as it raced east at over 40 mph, growing to nearly two miles wide.
By 6:16, Samaras and his team had turned east on Reuter Road, a major east-west artery. They were less than a mile north of the edge of the tornado. It was still zigzagging east southeast, but it was growing even larger. It took them three minutes to make it to US-81, the main north-south road in the area. They paused there for a moment. The tornado was nearly 2.5 miles wide at this point, the edge of the swirling mass obscured in heavy rain and less than a quarter mile south of them, and it was turning to the northeast.
Unbeknownst to Samaras’ TWISTEX team, as they continued east on Reuter Road, they were heading into the teeth of a monster. Speeding east, they began to encounter intense 70 mph head winds on the left side of the tornado that slowed their progress. The tornado was holding them back with its outer circulation, the winds in the powerful vortex approaching 300 mph according to Doppler radar data.
Before the TWISTEX crew reached Radio Road, their path intersected the tornado. There, a subvortex intercepted their White Chevy Cobalt and threw the car over 2,000 feet. It was recovered in a field east of the intersection of Reuter Road and Radio Road. Tim was found in the crushed car. The engine and three of the wheels were missing. Paul and Carl’s bodies were recovered near where the subvortex hit the car.
The El Reno Tornado was a terrible beast. Some of the frightening superlatives noted by the Doppler on Wheels according to Josh Wurman:
…As it neared Highway 81, it was moving at 55 mph. This contributed to the deaths of the TWISTEX team as the massive tornado overtook them.
…Subvortices inside the parent tornado were as large as other major tornadoes.
…There were actually tornadoes within other tornadoes.
…The DOW actually recorded a 255 mph velocity in a subvortex! (That’s the equivalent of an EF5 rating).
…The official width of the tornado was 2.6 miles, making it the largest on record. But the circulation was actually 4.3 miles wide at 300 feet according to the radar!
…The powerful circulation produced an anticyclonic tornado with winds measured at 145 mph.
It’s human toll was great: nine people lost their lives during the storm.
It was initially rated as an EF5, but that rating was surprisingly lowered to an EF3. Velocities measured by the DOW were well above the threshold for an EF5 rating, but the rating scale is a damage scale and since the tornado did not leave damage indicators that were consistent with those wind speeds, the official rating of the tornado went into the books as an EF3. Many argued that the reliable Doppler radar data gathered during the El Reno Tornado supported the EF5 rating.
One thing the El Reno Tornado did was remind thousands of professional and amateur storm chasers that the violent storms are unpredictable and deadly. Tim Samaras was widely known as one of the most respected and safest chasers in the business. If he could die in a storm, then it could happen to anyone.
Portland, OR was a major shipbuilding during World War II. As many as 100,000 people were employed in the shipyards. Thousands of people flocked to Portland, many of them African-Americans who had moved to the Northwest from the South. The huge influx of people created a huge housing shortage.
Vanport City was a federal housng project built on 650 acres along the banks of the Columbia River north of Portland. As many of 40,000 workers lived in the city of Vanport during the war. After the war, layoffs thinned the population, but 19,000 workers still lived in Vanport City in 1948.
Despite the fact that Vanport City was on the largest river in the western United States, there was little concern. The winter of 1947-48 produced heavy snowfall amounts in the upper Columbia River basin. Warm temperatures in the spring caused rapid melting of the snowpack, and rivers and streams quickly jumped their banks. Despite the rising water, there still was little concern.
On Sunday, May 30th, a dike which supported a rail track on the west side of the housing development suddenly collapsed. The crevasse widened from 6 feet to 60 feet and then to 500 feet wide. It only took two hours to flood the entire city. The following day, the dike on the eastern side of town collapsed also, sealing the town’s fate.
There was almost no warning for the town’s 19,000 residents. Twenty five people drowned. The residents of the town lost all of their personal belongings, most escaping with just the clothes on their backs. Ten thousand homes were destroyed. Damage totaled $21 million. Vanport would never be rebuilt. The area is now a flood mitigation zone with parks and golf courses.
They are just that. Scary clouds.
Several people around The Summit have been observing menacing looking funnel like clouds to the south over Double Oak Mountain. Here is an example from @jmdrennen.
These are harmless scud clouds developing as air is lifted by the cooler, moist outflow of nearby storms. Cloud fragments, known as scud, will form in mid-air or under the base that can protrude downward, appearing to be a funnel cloud.
These false funnels are distinguishable from true funnel clouds or tornadoes because they will not be rotating. They are also more ragged and often rising and descending intermittently.