2012 Tropical Cyclone Season Summary

In 2012, five tropical cyclones entered the Canadian Hurricane Centre (CHC) Response Zone (RZ) with two of those storms staying on the very edge of the zone.  The CHC issued bulletins on four storms, two of which affected land while the other two were purely offshore events. On September 11^th former Hurricane Leslie struck Newfoundland as a post-tropical storm, causing minor to moderate wind damage over the eastern peninsulas of the island.  Then, on October 29^th and 30^th the far-reaching influence of Post-Tropical Storm Sandy was felt over southern Ontario and other parts of Eastern Canada.  Regions of Ontario near the Great Lakes experienced minor to moderate wind and wave impacts.   

The offshore events included Post-Tropical Storm Chris, skirting the Southeastern Grand Banks on June 22^nd, and Post-Tropical Storm Rafael, racing across the southern fringe of the Grand Banks on October 18^th.  Tropical Storm Michael transitioned to a post-tropical storm over the extreme southeastern portion of the RZ and did not require bulletins being issued because of its small size and its distance from the Canadian marine forecast district.  

Unnamed tropical storm-force disturbance on the edge of the Grand Banks off Newfoundland

In addition to the conventional tropical events, there was one additional noteworthy cyclone which tracked over the outer fringe of the Grand Banks on July 25^th. The low was not named, but exhibited sub-tropical characteristics on satellite (below) and a compact wind field.  As a precaution, the Newfoundland and Labrador Weather Office, in coordination with the CHC, issued gale-force wind warnings for a small portion of the marine forecast district.

Below is a summary of the four primary events of tropical origin that affected Canadian territory in 2012.

• Chris
• Leslie
• Rafael
• Sandy

Chris

Storm

Hurricane Chris was an early but short-lived storm that was active between June 19^th and June 22^nd.  After forming around 35^oN from a non-tropical low which was associated with a frontal system, it tracked toward the east then looped north and northwestward on June 21^st and 22^nd while undergoing Extratropical Transition (ET).  A second non-tropical low formed to the south of Post-Tropical Storm Chris on the 22^nd – interacting with it in a manner which imparted an eastward motion on the post-tropical low before it dissipated.

Conditions

Because Chris was a purely marine storm, there were no impacts over land.  Only moderate north and northeast winds (15 knots) were measured at the Tail-of-the-Bank buoy at 42.9^oN 51.5^oW. 

Impacts

There were no known impacts on land or to offshore infrastructure.

Warnings & Information Statements

The CHC issued five unique information statements for this event.  Three to four metre waves were predicted and gale warnings were issued for the extreme southeastern portion of the Grand Banks off Newfoundland. 

Coordination and Communications Effort

The CHC and Newfoundland and Labrador Weather Office (NLWO) maintained close communication during the short life of Hurricane Chris. 

Leslie

Storm

Leslie formed from a disturbance in the deep tropical Atlantic in early September and travelled well northeast of the Caribbean Islands.  Over a five-day period from September 4^th to the 9^th the tropical storm/weak hurricane spent a prolonged period of time moving very slowly northward.  During this time, Leslie travelled about 500 km with a forward speed of only 4-5 km/h, impeded by a large high pressure system to the north.  When a front moved off the U.S. Eastern Seaboard on September 9^th, Leslie finally began to approach Atlantic Canada.  Then the front stalled over Nova Scotia as it approached Leslie.  Moisture converging along the front streamed across central Nova Scotia. On September 11^th, the tropical storm and front merged and tracked into eastern Newfoundland.  The official status of Leslie at landfall was ‘post-tropical’ with maximum sustained winds of 65 knots (120 km/h).  The landfall of the very broad centre was over the southern tip of the Burin Peninsula.  Minimum central pressure at landfall was 969 mb/hPa.

Conditions

Although it was not directly related to Leslie, the stalled front over Nova Scotia caused serious flooding with observed rainfall rates of 25 mm/hr.  This resulted in flash-type flooding around Truro, Stewiacke and Shubenacadie.  The rain fell in an area where flooding was exacerbated by return flow up the tidal rivers connected to the Minas Basin and Bay of Fundy.  The greatest total rainfall from the Leslie-stalled front was 165 mm (6.5”) at Shubenacadie, Nova Scotia.

Wind impacts were felt over eastern Newfoundland with greater than hurricane-force wind gusts from the south and southeast measured at several stations.  The highest gust of 137 km/h was observed at the very-exposed Cape Pine private station on the southern Avalon Peninsula.  A summary of wind and rainfall data appears below.

Fortunately storm surge was not an issue during Leslie’s landfall in Newfoundland.  This was due to local low tide and a neap phase in the tidal cycle.  The highest measured surge was 1.1 m in the communities of Argentia and St. Lawrence.

Impacts

Noteworthy impacts included uprooted trees, snapped power poles, damaged roofing and building cladding, broken signage, toppled fences and overturned trucks.  Some flooding occurred over western Newfoundland resulting in undermined roadways, lowland inundation and some stream overflows.  Coastal impacts seemed to be related to over-wash and wave-breaking causing minor damage to breakwaters and small structures. 

Warnings & Information Statements

The CHC issued 23 unique information statements for this long-lived event.  Several of these statements were issued while Leslie was nearly stalled to the southeast of Bermuda.  Tropical Storm and Hurricane Watches were posted for the eastern half of Newfoundland late on September 9th.  Tropical Storm Watches were upgraded to warning level during the morning of September 10^th, while Hurricane Watches were held until the center of the storm exited the northern coast of Newfoundland.  There were 12 public forecast zones under the warning, with all but one (~90%) experiencing warning-level winds.  Rainfall warnings verified correctly for 15 out of 19 (~80%) public forecast regions in Newfoundland.

Coordination and Communications Effort

The CHC and the NLWO maintained close communication during the long evolution of Hurricane Leslie.  Media interest was elevated over a prolonged period given the slow pace of the storm, and it was particularly challenging to communicate the forecast given the much greater-than-normal uncertainty.  The approach and subsequent stalling of a front well to the northwest of the hurricane also presented a communications challenge.  Many were confused as to which weather system was affecting their area, despite clear descriptions of the differences in the CHC reports.  This is a common challenge, given that the boundary between tropical and non-tropical systems is rarely well-defined.

Rafael

Storm

Rafael formed in the eastern Caribbean late on October 12^th and moved slowly northward, attaining hurricane status late on the 15^th.  Extratropical transition started almost as soon as Rafael became a hurricane and was complete by late on October 17^th as the storm’s cloud shield rapidly fanned-out while tracking about 200 km east of Bermuda.  Forward acceleration occurred on October 18^th while the hurricane-strength post-tropical storm traversed the southern Grand Banks off Newfoundland. 

Conditions

The southern coast of the Avalon Peninsula of Newfoundland experienced heavy surf generated by waves travelling northward as the storm moved along a straight north-northeastward trajectory.  Four to seven metre waves with a 16-second period were measured at the Nickerson Bank Buoy about 35 km offshore south of Trepassey, Newfoundland.  Elevated water levels were witnessed in St. John’s Harbour, likely from the rapid-tide effect described in special bulletins issued by the CHC and the NLWO (see ‘Warnings and Statements’).

There were few weather impacts over land.  The high cloud shield from extratropically-transitioning Rafael overspread Nova Scotia and Newfoundland.  Heavy rain associated with a front extending well north of Rafael passed not far offshore late on October 17^th.  Cape Race measured some moderate rainfall for a brief period, amounting to 6 mm. 

Waves were estimated to have been above 10 metres well offshore to the right of Rafael’s track.  No detailed information was available for analysis of the waves from this storm during the extratropical transition. 

Impacts

Large waves and run-up were the primary impacts along some southern coastline communities of Newfoundland.  In Trepassey, about 110 km south-southwest of the capital city of St. John’s, heavy surf tore apart a 10-metre section of a breakwater connecting two parts of the community and heavily damaged an additional 500-metre portion of coastal roadway.  More than $1 million in damages was estimated to have occurred in the area as a result of the far-reaching wave impacts.      

Warnings & Information Statements

The CHC issued 18 unique information statements for Rafael.  During its post-tropical phase, Rafael travelled rapidly across the southern Grand Banks with a forward speed near 45 knots (80-85 km/h).  Special statements were issued to alert the coastal communities in southeastern Newfoundland of rapid changes in water levels and ocean currents.  This unique effect occurs when sharp wind and pressure features rapidly cross shallow offshore waters.  Fortunately these fluctuations occurred before the local high tide, so there were no reports of flooding.  Hurricane-force wind warnings were posted for the southernmost portion of the Grand Banks.        

Coordination and Communications Effort

The CHC and NLWO maintained close communications during this event.  Although there was very little media interest in this event given the far-offshore track, a local newspaper reported on the unusual water level alerts on Thursday, October 18^th.

Sandy

Storm

Sandy formed in the southern Caribbean Sea from a very large area of cloudiness on October 22^nd.  Over the next two days the storm moved northward and became a hurricane as it approached eastern Jamaica.  Early on October 25^th, Sandy intensified to category-three storm and made landfall in eastern Cuba.  After leaving Cuba, Sandy tracked through the Bahamas in a weakened state, as a trough of low pressure approaching from the west created strong upper-atmospheric winds and eroded the thick clouds near the storms centre.  This attempt at extratropical transition (ET) was suspended as upper winds north of the Bahamas decreased and the thick clouds returned to the centre while the storm was over warm Gulf Stream waters.  The very large storm system continued to be influenced by upper-atmospheric low pressure troughs that created more rising air over the storm environment on October 28^th and 29^th, resulting in further deepening.  Eventually another trough entered the hurricane core of the large system, leading to the final ET process with strong upper winds over the center and the development of surface fronts.  This process occurred just before landfall near Atlantic City, New Jersey when the central pressure had risen slightly from a low of 940 mb to 945 mb.  The post-tropical storm tracked west-northwestward into Pennsylvania on October 30^th then dissipated on the 31^st. 

Conditions

The intense post-tropical storm caused extensive damage over a large portion of the Eastern Seaboard of the United States near and well outside of the landfall point in New Jersey.  The circulation extended well into Eastern Canada and the Great Lakes.  High winds gusted from the north and northeast over southern Quebec and Ontario.  Warm southeast winds blew into Atlantic Canada.  Wind blowing down the length of Lake Huron resulted in high waves and storm surge, with seas of five to seven metres measured at buoy 45149 in the southern end of the lake. 

Select wind and rainfall data from Canada appear in the table below:

*Bridge connecting Canada and the U.S. at Sarnia, ON.  Note however that the wind instruments are atop the bridge, around 60 m – six times higher than the accepted standard 10-metre height for wind measuring instruments.  

Rainfall was not a significant issue in Canada.  The greatest measured amount was 55 mm in Charlevoix, Quebec, while all other primary reporting stations received less than 50 mm. 

Waves approaching the south shore of Nova Scotia were in the range of five to eight metres (e.g. buoy 44150).  These waves resulted in elevated water levels up to 60 cm along parts of the Atlantic coast in western Nova Scotia. 

Impacts

High wind gusts downed tree limbs and whole trees leading to numerous power outages across southern Ontario.  There were a few reports of trees falling on vehicles and homes causing significant damage.  Sandy implicated in two fatalities in Canada – one in Toronto when a large sign was blown down and struck a pedestrian.  The second occurred in Sarnia, Ontario, when a hydroelectric worker was electrocuted during the post-storm cleanup.  The Sarnia area was hit particularly hard as a result of strong north winds off Lake Huron in addition to storm surge and heavy surf.  The city was littered with downed trees and power poles, with some reported structural damage to buildings including part of a roof blown off a hotel.  Over $10 million in private property damage was estimated to have occurred.   Fierce winds and record-high waves disrupted cargo ship travel through Lake St. Clair and the adjacent waterways connecting Lake Erie and Lake Huron.

Warnings and Information Statements

Wind warnings were posted for many portions of southern Ontario and parts of Quebec near the St. Lawrence River.  Warning-level winds materialized in Ontario.  Rainfall warnings were not issued except for the Charlevoix region of Quebec.  Various marine warnings were issued including storm-force winds over Lake Huron.

The CHC issued 18 unique information statements for Sandy, commencing on the afternoon of Thursday, October 25^th.  Another statement was issued on Friday, followed by regular statements issued every six hours beginning on Saturday morning, well ahead of the worst of the weather (which arrived in Ontario during the early hours of Tuesday, October 30^th).  The final summary bulletin from the CHC was issued at 3 pm ADT on October 30^th.  There were no official tropical-type watches or warnings since much of Sandy’s transformation to a post-tropical storm began before landfall in the U.S.

Coordination and Communications Effort

There was an unprecedented amount of media interest and interoffice communications due to the broad expanse of the storm’s impact.  The challenge in Canada was to effectively communicate the threat and how it differed from what was happening in the U.S.  This was not unlike the challenge that existed in 1985 with Hurricane Gloria tracking into Canada from the U.S. – interestingly, the weather event that served as the catalyst for the creation of the CHC.  Hurricane Sandy’s extratropical transition and uncharacteristic northwestward track into New England was very well predicted by the numerical weather models, well in advance.  This permitted very early communication (five to seven days ahead of the event) to occur between the CHC, all of the Meteorological Service of Canada’s eastern and national centres and emergency management partners.  The threat of rainfall was communicated earlier during the evolution of Sandy, but as time elapsed, the threat of rain-related flooding decreased.  Details about wind impacts were emphasized closer to the event. On Monday, October 29^th, the CHC and Ontario Storm Prediction Centre alerted areas around southern Ontario of specific wind-related impacts such as falling trees and power outages.