Gaps in National Doppler Radar Coverage Exacerbate the Risk of Truck Accidents Due to Severe Weather

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    Any individual from a near-novice driver to an experienced professional CDL driver understands that poor weather conditions can greatly increase the risk of a severe truck accident. Weather-related risks can include large snow and ice storms. However, most drivers are aware of the threat and risk posed by a major storm and can therefore work around the event. However, most experienced drivers are also aware that winter weather can produce hazardous conditions with significantly less advance warning.

    For one, in the days and weeks following a snow storm, the melting of snow banks that may pile up along the sides of highways and roadways may run onto the road surface. Overnight, this snow melt refreezes creating black ice that can take even a cautious and experienced driver by surprise. Unfortunately this is not the only risk. Many drivers are surprised to learn that moderate pop-up storms that can drop inches of rain or snow over the course of only a few hours can also take drivers by surprise along some stretches of roadways. Furthermore, in the spring and summer, intense rapidly forming squalls that spawn small tornadoes can also go undetected.

    The reason the threats go undetected and cause serious accidents and deaths on highways and trucking routes is due to gaps in the national Doppler radar system. These gaps allow for small, intense storms to form and wreak havoc on communities and the roadways with little or no advance warning.

    The Importance of Doppler Radar to Truck Drivers & the General Public

    Before the age of smartphones, it wasn’t uncommon for weather enthusiasts and others to watch the loop on the Weather Channel to see the local Doppler radar. From this information they could generally see weather patterns develop and predict the conditions for the today. In today’s world of smartphones and instant electronic communications, most people have at least one app that can pull down the local radar based on their GPS coordinates. Others may simply use their web browser and zip code to pull down the information. However, it is a safe assumption that most people whose job or activities will require travel or significant amounts of time outdoors make use of this technology. Now, radar isn’t the only way truck drivers and others get information. However, if you hear someone talking about a line of storms approaching I-95 at a certain time over CB, odds are that radar played a role in delivering this information.

    Unfortunately, many of us simply take weather maps that can be accessed whenever the need arises for granted. However, the availability of this information is dependent on a nation-wide system of radar arrays. Furthermore, the most important part of the radar network is low-level coverage. Low-level radar coverage is essential because radar waves travel in straight lines and the spherical nature of the earth causes radar waves to travel further and further from the ground as the distance the signal travels increases.

    The reason low-level coverage is important is because its absence can result in missed storms and other weather events. For instance, in July 2015, a gap in radar coverage – specifically low-level coverage – resulted in the National Weather Service (NWS) missing and EF-2 tornado. The tornado traveled roughly 18 miles in distance and reached a width of 150 feet. NWS never issued a warning about the tornado. When asked by the Washington post about the failure to issue a tornado warning, NWS meteorologist Jim Kaiser blamed the radar gap stating “The tornado and how small scale it was, and you try to figure that we’re looking at 7,000 feet above that circulation. You’re never gonna see it on radar.”

    How Can the National Radar System Have Gaps that Potentially Endanger Truckers & Other Motorists?

    Generally, there are two main reasons for gaps in radar coverage. The first is due the distribution of radar stations across the nation. While the federal government has done a relatively good job of distributing the stations such that most areas with significant populations are covered, not all areas have low-level coverage or any coverage. For truckers, this means that in most metro areas are covered and they should receive advance warning of conditions when in these zones. However, rural drivers and long haul drivers who pass through sparsely populated areas will not benefit from the advance warning provided by radar.

    The second reason why radar gaps exist comes down to the age of some parts of the radar system. The systems were deployed, largely, in the post-World War 2 boom years during the 1950s and 1960s.  The government attempts to keep these systems maintained and running, but in our current era of decreased federal spending, maintenance may be deferred until things break.

    For instance, in July 2013 the radar array in Albany, New York (KNEX) experienced a catastrophic hardware failure. The NWS issues a statement:


    The radar system was down from July 16, 2013 until early August. However, hardware failure due to age isn’t the sole reason for system failures. According to the Washington Post, on April 29, 2014, the Mobile, Alabama radar site was knocked offline due to direct lightning strike. This downtime unfortunately coincided with a historical rainfall and flash flooding event that washed out roads and caused catastrophic flooding throughout the area.

    While the first problem can be entirely remedied through careful planning, the second problem can likely be only partially remediated. While the likelihood for hardware failures can be reduced through more extensive maintenance, the problem posed by severe weather events cannot.

    Consequences of Radar Gaps Include 64 Car and Truck Pile-Up on I-78 in Pennsylvania’s Due to Snow Squalls

    Last week, a major 64-vehicle pile-up including at least 10 tractor-trailers occurred. states that roughly a dozen commercial trucks including box trucks and tractor-trailers were involved in the wreck. The accident was catastrophic. 9-1-1 calls at the time indicated that at least 15 people were trapped in their vehicles. More than 70 drivers were sent to the hospital due to injuries suffered in the wreck. Three drivers were fatally injured in the crash. The accident occurred at 9:30 a.m. but was so severe that the highway was shut down in both directions the entire day and into the early morning hours of the next day.

    The reason the accident was so severe is drivers were taken by surprise because this area is part of one of the more populated areas where a radar coverage gap exists. The radar station that services this area of the state is located in State College, Pennsylvania  (KCCX). The distance from State College to Scranton is roughly 150 miles meaning that resolution in the area is less than ideal. The area including Harrisburg Pottsville, Scranton, and Wilkes-Barre is one of the most populated areas with a radar coverage gap with about 1 million residents. Furthermore, significant amounts of commercial truck traffic pass through this area since major highways including the Pennsylvania Turnpike, I-78, I-80, and I-81 pass through the area.

    The forecast for the day did not call for any significant snow storm, but a pop-up snow squall took all commuter and commercial motorists by surprise. The lack of advance warning from a radar system likely caused or exacerbated this 64 vehicle accident. Had a radar system been in place, NWS could have issued a warning. Then, PennDOT and the Pennsylvania Turnpike Commission could have issued warnings to motorists, asked troopers to slow down traffic, or posted reduced speed and weather warnings. However, PennDOT and the PA Turnpike Commission did not have this information to provide advance warning or other corrective action. While we cannot say that the accident certainly would have been avoided if the radar information was available, at minimum, the information would have reduced the likelihood of the crash and ensuing pile up.

    Where is the Worst Radar Coverage Gap in the United States?

    While the radar coverage gap in Pennsylvania is certainly one of the worst in the nation, the gap around Charlotte, North Carolina is the worst in the nation. In fact, Charlotte is the largest city in the nation without low-level coverage. Greenville, SC (KGSP) and Columbia, SC (KCRX) are the nearest stations but are each more than 80 miles away from the city. This means that a major stretch of I-85 from Charlotte towards Greensboro receives no low level coverage. This is certainly the worst gap in the nation, however other gaps also exist. Other major gaps include:

    • Florida – For the entire width of the peninsula – from the Orlando-Tampa are up to south of Jacksonville and Tallahassee – there is a radar coverage gap. This means that parts of I-4, I-75, and I-95 do not have low level coverage.
    • Texas – At least three major gaps exist in Texas with two in the highly trafficked areas. These includes the northeast of Austin and I-45. The northeast of Dallas is also uncovered meaning that parts of I-30 and I-75 lack low level coverage.
    • South Dakota – The state capital, Pierre, is entirely uncovered by low-level radar. Drivers and truckers on I-90 and other major roads will not receive advance warning of storms.
    • Michigan/Ohio – South of Detroit, starting around Toledo, Ohio there is a gap in radar coverage. This coverage gap includes part of I-90 and I-75.

    There are still other major radar gaps in the United States including large expanses of land and highways west of the Rockies. Drivers should not only be aware of the road conditions but also gaps in radar coverage that may result in unexpected weather conditions such as severe thunderstorms, snow squalls, and tornados arising without warning.

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