Canadian Hurricane Centre Meteorological Service of Canada 45 Alderney Drive Dartmouth, Nova Scotia B2Y 2N6 canada website

(Right): Tree-related damage in Charlotteown, PEI (The Guardian)

There were 26 unique information statements (WOCN31 CWHX) issued by the CHC for this event. Tropical storm warnings were posted over the southwestern Maritime Provinces. Regular wind and rainfall warnings were issued in Quebec since the storm had become post tropical as it was affecting that region. The transition was most apparent with the warm front development combined with topographic effects on the wind in the St. Lawrence Valley region. Gale to storm-force wind warnings were issued for most Atlantic Canada waters and the St. Lawrence River region.

The CHC conducted daily conference calls at 3:30 pm ADT for operational weather offices in Eastern Canada. These included the Quebec Storm Prediction Centre, Canadian Meteorological Aviation Centre, Atlantic Storm Prediction Centre, and other groups including Warning Preparedness Meteorologists in Quebec and Atlantic Canada. Planning meetings were held daily around 9:30 am ADT with Environment Canada Department Heads in Atlantic and Quebec regions to maintain coordination on various activities. Daily briefings were given by the Warning Preparedness Meteorologists for Sécurité Civile du Quebec and emergency managers in the Maritimes, both federally and provincially.

Hurricane Katia formed off the Cape Verde Islands on August 30^th and travelled northwestward for almost 9 days, intensifying to category-4 strength briefly on September 6^th. With its persistent northwestward tracking, Katia generated large waves that crashed ashore over the Atlantic coast of Nova Scotia and southern coast of Newfoundland. On September 9^th, Katia took a sharp turn toward the northeast and accelerated rapidly on September 10^th while passing south of Newfoundland and undergoing extratropical transition.

The lowest estimated pressure over Canadian waters was 955 mb which occurred during the latter stage of extratropical transition. Although the cloud shield associated with Katia shrouded much of the Atlantic Provinces, the precipitation stayed well offshore. Rainfall at Sable Island (about 300 km north of Katia’s centre) was only 20 mm but totals between 60 and 120 mm would have been likely if the centre tracked over land.

* Sustained wind is a 10-minute mean at the 5-m level above water surface. Gust is a 5-s peak over a 10 minute interval near the top of the reporting hour

The only known impact to land territory was minor wash-up of debris from large waves travelling north of the hurricane. At least one incident was reported along the south shore of Nova Scotia when someone was caught up in rip currents at a local beach.

There were 22 unique information statements issued by the CHC for this event. No warnings were issued for land territory except a special statement for abnormal coastal water levels around the eastern portion of Newfoundland due to a known oceanographic phenomenon (a “rapid tide” effect) that has caused flooding in the past. The predicted oscillations in water levels did occur but fortunately were not present at high tide.

The Newfoundland and Labrador Weather Office in Gander and the Canadian Hurricane Centre in Dartmouth maintained close communication while Katia was affecting offshore waters. Special attention was given to the coastal water level statement to ensure clear terminology and communication to the public. Warning Preparedness Meteorologists coordinated with provincial and federal emergency management officials.

Maria formed on September 7^th in the mid tropical Atlantic and tracked westward then northwestward, skirting the Caribbean Islands from September 10^th to 12^th. Maria – while still a tropical storm – moved northward to the west of Bermuda and attained hurricane status on September 15^th at 35^oN latitude. Hurricane Maria accelerated toward the northeast thereafter, making landfall in Newfoundland on the afternoon of September 16^th as a strong tropical storm in the Cape St. Mary’s/Argentia area of the Avalon Peninsula. After transition to a post-tropical storm while exiting Newfoundland, Maria merged with a large non-tropical low that had been intensifying over southeastern Labrador. The combined low was actually a more potent storm for northern Newfoundland and Labrador on September 17^th.

The central pressure of Maria at landfall was estimated to be 985 mb. Strongest winds with the storm were to the right of its track. The highest winds were far enough from the centre at landfall such that they did not pass over land. The maximum wind jet was just offshore to the east of the Avalon Peninsula. The remnant eye of Maria covered most of Placentia Bay and up into the Clarenville area of the province just prior to nightfall. Winds were observed diminishing to light as the “eye” passed with partially clearing skies, followed by a modest increase in wind speed and returning cloud cover after the centre moved away.

* Private or volunteer observation

* Sustained wind is a 10-minute mean at the 5-m level above water surface. Gust is a 5-s peak over a 10 minute interval near the top of the reporting hour

Impacts from Maria were quite minor, since the highest winds remained offshore. There were only a few reports of light objects being blown off private properties. For a land falling storm near hurricane-strength, there were surprisingly no interruptions to the power grid.

There were 18 unique information statements issued by the CHC for this event. A hurricane warning was issued for the southern part of the Avalon Peninsula of Newfoundland while a tropical storm warning was posted for remaining parts of the peninsula as well as the Burin and Bonavista Peninsulas. The strong winds did not materialize over land, and the warnings were quickly ended once forecasters became aware that the highest winds were remaining offshore.

Close communication was maintained between the Newfoundland and Labrador Weather Office in Gander and the Canadian Hurricane Centre in Dartmouth. Technical media briefings via WebEx were given during the days prior to the storm’s arrival by the Head of the CHC and the Warning Preparedness Meteorologist. Warning Preparedness Meteorologists took part in regular federal and provincial emergency management briefings for the island of Newfoundland leading up to the event.

During the evening of September 15^th, the National Hurricane Center changed the forecast from a glancing-blow tropical storm to a direct-hit hurricane landfall in Newfoundland. After a detailed discussion between the NHC and the CHC, a decision was made to issue a tropical storm warning and hurricane watch for the Avalon Peninsula, with a lead time of about 21 hours. The hurricane centers continued to coordinate on watches and warnings for the remainder of the event.

Hurricane Ophelia

Storm

Ophelia formed in the mid tropical Atlantic on September 21^st and tracked northwestward as a tropical storm over the following week. It was not until September 30^th when Ophelia began to move on a more northerly course that it strengthened to hurricane strength. In fact, Ophelia rapidly intensified from tropical storm strength to category-3 intensity in 24 hours. The storm intensified further to a 940-mb category-4 hurricane while tracking northeast of Bermuda on October 2^nd. The compact hurricane entered the CHC Response Zone as a strong category-3 then rapidly weakened as it travelled over cooler ocean water temperatures. The weakening occurred quickly enough so that Ophelia dropped below hurricane strength as it made landfall on the Avalon Peninsula of Newfoundland near the community of Placentia. The storm centre appeared to reform approximately 50 km north of landfall, then track north of the capital city of St. John’s.

The central pressure of Ophelia was estimated to be 988 mb at landfall. Maximum winds at landfall were near 55 or 60 kts (100-110 km/h) about 50 km offshore. Wind gusts to 100 km/h were reported along the immediate southern coastlines of the Avalon and Burin Peninsulas. Inland gusts near 80 km/h were reported. These wind speeds are not unusual for Newfoundland. Winds noticeably diminished as the centre of the storm passed through, then increased from the west, gusting to near 90 km/h after the storm core moved away. The primary wind and rainfall figures are found in the table below. Rainfall was light near the center of the storm and to its right, as is typical for extratropical transition. Not far to the left of the track, heavy rainfall came quickly – amounting to near 50 mm in 3 hours.

* peak one-hour rainfall just over 20 mm and 3-hr totals near 50 mm

* Sustained wind is a 10-minute mean at the 5-m level above water surface. Gust is 5-s peak over a 10 minute interval near the top of the reporting hour

Impacts from Ophelia primarily came in the form of flooding due to rainfall. The region most affected by heavy downpours was the Burin Peninsula which was also hit hard during Hurricane Igor the previous year. A drainage ravine overflowed in the town of Belleoram, sending a cascade of rocks, mud and water into some homes causing heavy damage to a couple of buildings. A brief state of emergency was declared in the community.

(Right): Cascade of rocks caused by flash flooding in Belleoram – RCMP “B” Division, NL

There were 18 unique information statements issued by the CHC for this event. The CHC maintained a conservative forecast for this event, issuing nothing “stronger” than a tropical storm watch for the Avalon Peninsula of Newfoundland. However, hurricane-force warnings were issued for the offshore forecast district. Rainfall warnings were issued for the hardest-hit areas including the Burin Peninsula.

Similar to Hurricane Maria, close coordination was maintained between the Newfoundland and Labrador Weather Office and the Canadian Hurricane Centre. The CHC emphasized the importance of not over-warning the winds for the event. Regular briefings took place between federal and provincial emergency managers. The conservative approach certainly paid off, as Ophelia’s winds fell short of the conventional wind warning criteria for the island (gusts of 100 km/h or more).

Dr. Chris Fogarty, Program Supervisor, Canadian Hurricane Centre

John Parker, Manager, Prediction and Training Section.