Superstorm Sandy

Superstorm Sandy began its life as a tropical storm approximately 600 kilometres south of Jamaica on October 22, 2012. During the course of the following days it would transition into a hurricane, striking Jamaica, Cuba and the Bahamas. As it moved northwards from the Bahamas, it would begin to exhibit the characteristics of both a hurricane and a mid-latitude fall storm.

By the time it made landfall in New Jersey on the evening of Monday, October 29, it had completely transitioned into a mid-latitude fall storm – albeit a massive one, with a diameter in excess of 1,600 kilometres. The combination of Sandy’s winds, rain, storm surge and snow would leave 135 people dead and loss estimates in the United States ranging from $50-$65 billion dollars.

The impacts in Canada, while not on the same scale as those on the U.S. Eastern Seaboard, were still noteworthy: the loss of two lives in Ontario, 150,000-plus homes without power in Ontario at one point, and approximately $100 million in insurable losses in Ontario, Quebec and Atlantic Canada. A good portion of those losses occurred in the Sarnia and Lambton County areas; the winds from Sandy came howling from the north right off Lake Huron.

Much has already been written about the rare “hybrid” nature of Sandy, and over the coming years the data gathered during Sandy’s life will be analyzed and reanalyzed. Many experts have referred to this event as a “once-in-a-lifetime” storm which combined the elements of a hurricane with those of a massive fall storm.

The storm also renewed debates about the best ways to protect cities near oceans and what role climate change may have played in its creation. While the answers to these questions are not readily available, Sandy has opened the discussion on how best to adapt to the potential for more storms of this nature in the coming years.

One of the best ways to describe Sandy’s lasting legacy will be the fact that this could be the storm that “launches a thousand dissertations.” Many Ph.D. theses in the coming years in Atmospheric Science, Climate Science and Emergency Management will be drawn from how Sandy formed, evolved and impacted the U.S. Eastern Seaboard.

Sandy also provided an opportunity to demonstrate just how much weather modelling has improved over the last couple of decades. The ECMWF (European Centre for Medium-Range Weather Forecasts) prediction model uses a very powerful computer and has been designed to forecast the weather in the 3-to-10-day timeframe. Even as Sandy was in its formative stages on October 23, the ECMWF model was predicting a rare westward turn in Sandy’s track into the northeastern seaboard of the U.S. six days into the future. At this point, the ECMWF model was somewhat unique, with models from Canada, the U.S. and the U.K. indicating a more traditional track for the storm keeping it out over the Atlantic.

Given the skill shown by the ECMWF model in the past, and the fact that its forecast track could potentially impact portions of Ontario, Quebec and Atlantic Canada with strong winds and rain, a preliminary e-mail was sent to key provincial and municipal contacts within Ontario on October 23 mentioning the possibility of significant weather a full six days into the future.

This e-mail represented an example of the type of “early notification” to key clients that Environment Canada would like to develop more fully in the coming years. The form that this early notification may take could change in the coming years, but the main issue is to try to inform key stakeholders about potentially significant weather in the 3-to-7-day timeframe – when forecaster confidence may not be high, but the event is growing in probability. Once forecaster confidence about the event has grown, then formal messaging to the media and general public (i.e., Special Weather Statements, Watches and Warnings) would follow.

 As the days went by and other forecast models began to follow the track originally forecast by the ECMWF, and forecaster confidence grew, a Special Weather Statement was issued by the Ontario Storm Prediction Centre on Friday, October 26, for much of Southern Ontario. The statement mentioned the potential of damaging winds and heavy rain from Sandy as it made its anticipated landfall in the northeastern U.S. on Monday, October 29. By Friday, October 26, the Weather Centres in all affected regions (Toronto, Montreal, Dartmouth and Gander) were closely co-ordinating to ensure common messaging for this event. This co-ordination included internal technical briefings, briefings for key provincial government clients and media briefings.

As Sandy neared the U.S. coast during the early morning hours of Monday, October 29, the forecasters in Toronto realized that wind would be the main concern in Southern Ontario. So, a Wind Warning was issued for this area, mentioning gusts to 90 km/h or more. With the winds forecast to come from the north, the region that was expected to receive the highest gusts was the Lambton County area (as the winds blew in from Lake Huron).

Sandy made landfall at about 8 p.m. on Monday, October 29, bringing with it the various types of damaging weather that had been mentioned in the National Weather Service warnings. Because Sandy hit around the time of high tide, the damage from its storm surge was even more severe. The storm surge was accompanied by damaging winds, significant rain and, in portions of Ohio and West Virginia, significant amounts of snow as cold air was drawn into the system from the north.

In Ontario, winds began to pick up on the evening of the 29th, with many locations reporting wind gusts of 80 km/h or more into the early morning hours of Tuesday the 30th. As anticipated, Lambton County received the highest wind gusts and most significant damage, with gusts as high as 100 km/h. Another impact over the south end of Lake Huron was the creation of 7 metre waves from the strong and persistent winds from the north. This led to direct impacts on Great Lakes shipping as many large lakers had to hold up on the west end of Lake Erie unable to transition up through Lake St Clair and into Lake Huron with waves of this height.

A witness along the shores of western Lake Erie during that Monday evening remarked that it looked like a floating city of lights given the number of lakers waiting for the winds to die down. The strongest gusts diminished over most of Southern Ontario by mid-morning on the 30th except in Lambton County and over southern Lake Huron, where strong gusts continued for much of the day.

Extensive media coverage accompanied the days leading up to, during, and in the aftermath of Sandy’s landfall. In Ontario, more than 200 media requests were handled from Saturday, October 27, through Tuesday, October 30. One of the issues faced by Environment Canada spokespeople concerning this event was attempting to separate the American impacts of Sandy from the Canadian ones. Some Ontario media outlets had assumed there would be greater impacts in Ontario, based on the reports about Sandy coming out of the U.S., and so some time was spent to explain the differences and to provide more context concerning the Ontario impacts.

In summary, Sandy was a very rare storm that combined the ocean-driven energy of a hurricane with those of a massive fall storm system. No storm quite like Sandy had been documented before, but its method of birth and evolution will be a source of research for a number of years to come. It dramatically demonstrated the vulnerabilities of large cities along the U.S. Eastern Seaboard, where approximately 20% of the American population is found. While the worst impacts from Sandy were along the U.S. northeast coast, the storm was so immense that its impacts were felt well into Ontario, Quebec and Atlantic Canada.

The storm also provided evidence of the increased ability for weather models to provide useful guidance a full seven days before an event. This has impor
tant ramifications for the ability of weather services like Environment Canada to provide some form of “early notification” well in advance of large-scale events of this nature.

Now that the ability to provide advance notice in this kind of timeframe has been demonstrated, more work needs to be done in the coming years to determine the best avenues to share this type of information with key clients and the general public, and how best to express the uncertainties involved in the forecasting of these events.

Geoff Coulson is a Warning Preparedness Meteorologist with Environment Canada.