14:41 Mon Apr 12, 2021
Big Wind Day 2021
In years past, this annual blog post has taken a scientific approach and described the overall weather pattern of the system that brought several 220+ mph and two 231 mph wind gusts out of the SE, which is a relatively uncommon flow pattern. Each, from a slightly different perspective, which over time, has built quite a robust history of the event on our Blog. There are three, in particular, that stand out to me written in recent years, and after these brief synopsis', I encourage you to go back and read them as well. There is a lot to appreciate about that day, now 87 years ago, and I found this to be an opportunity to appreciate more than just one or two aspects of what occurred then.
The first written last year, the 86th Anniversary of the “Big Wind”, Dr. Eric Kelsey. I found this post to be of interest to me because it makes the connection between the instruments, the effort involved with maintaining the instruments during such an event, the calibration, and the process of verification of this world-breaking wind gust record. The article begins with a synopsis of the weather event and how it evolved, which is not dissimilar to how some systems continue to form to this day, but each system is unique and this one packed one heck of a wallop to the summit of Mount Washington (figure 1). “The skies just two days before were crystal clear and the winds were unusually light. Around sunset offered the first harbinger of the storm to come: reddish cirrus clouds to the west and a pair of sundogs. Those cirrus clouds were advancing eastward from an extratropical cyclone of moderate intensity tracking eastward through the Great Lakes. On 11 April, it moved into southern Canada while a stronger secondary low developed off the mid-Atlantic coast. Concurrently, a high pressure center retreating northeastward from Maine into the Canadian Maritimes also strengthened and became stationary over Labrador, which increased the pressure gradient between the coastal low and the high.
Figure 1: Sea-level
pressure analysis valid 9:00 a.m. EST on 12 April 1934 just hours before the
231 mph gust. A low pressure system centered just south of New England
intensified and tracked slowly northwestward during the day. From the U.S.
Weather Bureau (now the National Weather Service).
A third feature became involved and may have been the critical disturbance to intensify the summit winds to over 200 mph. A weak low pressure system just northwest of Bermuda tracked northwestward and was absorbed by the developing coastal cyclone south of New England. The merging of these two cyclones increased the strength of its circulation and the southeast winds to its north across New England. With the blocking high pressure over Labrador preventing the typical northeast advancement of the cyclone, the pressure gradient tightened across New England and produced over 24 hours of winds over 100 mph at the summit Mount Washington.”
Another feature of this system is the length of flow from the southeast to northwest, and the slight dip towards the southwest in the lines of equal pressure, isobars (figure 1). Flow generally moves along these lines. Given the distance and described temperatures changes in the next article, these winds had ample time and energy to build as energy was absorbed from the water of the spring time warming Atlantic. Then, there appears to be a dip and tightening of the isobars above northern New England, which would likely nudge them even higher.
Following the weather synopsis, the article goes on to explain the happenings of the events, and what actually went into the recording of the 231-mph wind gust. De-icing the Heated Number 2 anemometer (figure 2) in winds over 150 mph, prior to the record wind gust, I find it hard to imagine, even as one of the current observers on the summit. The difficulties Sal Pagliuca, Alex McKenzie, and Wendell Stephenson (“Steve”) must have dealt with astound and also motivate me.
MWO Observers Alexander McKenzie (left) and Sal Pagliuca (right) check the
tension of the guy wires on the Heated Number 2 anemometer.
The second blog post I’d like to bring your attention to was written in 2018, “Big Wind Day” by past Weather Observer, Taylor Regan. This article, I appreciate because it delves into the depths of the daily weather maps of the time period and quoted some of the observations made from around the eastern US. The following from Washington, D.C., Thursday, April 12, 1934 – 8 A.M. (E.S.T.); “A disturbance of great intensity is central this morning over Connecticut, New Haven, 29.26 inches. Pressure is high from the Rocky Mountain region eastward to the Mississippi Valley, Rapid City, S. Dak., 30.54 inches.” Regan also took snippets from the observer log book and quoted Sal Pagliuca "I dropped all other activities and concentrated on observations. Everyone in the house was ‘mobilized’ as during a war attack and assigned a job. The instruments were watched continuously so that they may give a continuous and accurate record of the various meteorological elements at work. The anemometer was particularly watched. A full tank of gasoline made us feel good." -Log Book entry, Sal Pagliuca. The intent and conciseness of the above quote really describes the seriousness of the day. Another quote stands out to me due to its caring nature for the integrity of data and I extrapolate to character as well; "Will they believe it?' was our first thought. I felt then the full responsibility of that startling measurement. Was my timing correct? Was the method OK? Was the calibration curve right? Was the stopwatch accurate?" -Log Book entry, Sal Pagliuca. Questioning yourself after such an event, I believe, to a natural thing to do when you truly care about the integrity of your work.
The last article I want to bring your attention to is not the least important one, but just the one I read last in this set of three as I went through the years. "Will They Believe It?": The Story of Big Wind Day - past Weather Observer, Mike Carmon brought the previous two full circle and back to the present day, which I found to be a fascinating experience. It made me think about the more intricate and personal experiences of the Observers, two friends of Sal’s and three cats with a litter of 5 kittens less than a week old.
It is hard to imagine what a 231-mph wind gust sounds and feels like. I imagine it from my own perspective, which is from the inside of a building constructed around 45+ years later, at a different location on the summit. The Mount Washington Observatory leases space on the NW end of the New Hampshire Mount Washington State Park, Sherman Adams Building. My own experience with high winds is from this perspective; a more modern (40-year-old building with a complete heating system, re-enforced concrete walls, and windows that should be able to withstand 300-mph winds. Having said that, it's not like high winds don’t have an effect on the Sherman Adams Building. High winds have multiple impacts on the buildings and structures on the summit and what I find so interesting are the different effects that wind direction has.
The predominant flow regime over the summit of Mount Washington is from the W, with the second most common flow regime from the NW. The current instrument tower is positioned in the NW quadrant as the most northwestern structure on the summit. The positioning of the Observatory and the instrument tower is thought to be the most accurate position to record the predominant flow over the summit. Back on April 12th, 1934, the day the infamous 231-mph Big Wind occurred, the Observatory was positioned on the SE quadrant of the summit with obstacles such as a hotel to the west and southwest of the Observatory. It was an A-Frame style roof, constructed of beams with wood shingles as the exterior. The small structure (figure 3), was the kitchen, their sleeping and dining quarters, their work station (figure 4), their maintenance workspace, their heating space, drying space. Everything was done in the building below. The Sherman Adams Building gets pretty cold in high winds and cold temperatures. During some events, it can be difficult for the weather room, and the rest of the building to maintain heat. I can only imagine how difficult it was to maintain the heat in the early 1930s structure with winds in excess of 200 mph pulling the heat right out. Or any of the tasks that current observers complete today, but 87 years ago.
Figure 3: Unknown observers tending to their duties in the
original Observatory building.
Figure 4: Data being recorded into a logbook at a
All three of the blog posts discussed in this years “Big Wind” celebration blog post, exhibit varying aspects pertaining to the storm system, the instruments and grueling work involved in their maintenance, the integrity and quality of the data through its verification process, and what those fabled three observers went through and felt throughout April 12th, 1934. I hope I helped to encompass all of these qualities in this year’s “Big Wind” blog post. To this day, the 231-mph wind gust stands as the fastest wind speed that has ever been observed and recorded by humans.
Jay Broccolo, Weather Observer/Meteorologist