A sprawling low-pressure system will combine with the return of some colder air in the Maritimes to create a very icy situation for parts of the region Wednesday into Thursday. This comes on the heels of a very warm Tuesday that saw high temperature records broken in the Maritimes. Record setting warmth on Tuesday It was so warm on Tuesday that new high temperature records were set in the Maritimes. The warmest temperature in the region at weather stations operated by Environment Canada was at St. Stephen, N.B., which reached 21.3 degrees. That is the first 20 degree temperature in the Maritimes for the calendar year and broke the previous record of 17.8 set at St. Stephen on March 10, 1977. Other communities in the Maritimes that set records include: Warnings issued for Wednesday into Thursday The weather can turn on a dime at this time of the year, and it does just that Wednesday into Thursday. A Yellow Warning for a winter storm has been issued for northern New Brunswick. The affected counties can expect 15-to-25 cm of snow and ice pellet accumulation on Wednesday. That is followed by a turn to freezing rain Thursday morning and then rain Thursday afternoon. A Yellow Warning for freezing rain is issued for parts of central/southern New Brunswick and Prince County, P.E.I. An initial mix of snow and ice pellets will turn to freezing rain Wednesday evening. The freezing rain may be ongoing for a period of four-to-eight hours before turning to rain Thursday morning. Environment Canada cautioning that “Roads and walkways will likely become icy and slippery. Property or tree damage due to the weight of ice is possible.” Some of the southernmost areas of New Brunswick are under a Special Weather Statement. Following some snow and ice pellets, those areas are at risk of two to four hours of freezing rain Wednesday evening and night. Impacts from Ontario to Atlantic Canada This is a sprawling, slow-moving weather system. The area impacted by significant freezing rain over the next few days stretches from Ontario into Atlantic Canada. If travelling into the St. Lawrence River Valley of Quebec, be aware that the freezing rain is expected to be even more severe there, extended for a longer period with more ice accreting. When it comes to freezing rain, it is the amount of ice collection, known as accretion, that occurs on surfaces that determines much of the impact. Accretion up to five millimetres creates slippery surfaces and can make for tough travel by vehicle and foot. Ice accretion of five-to-10 mm causes more issues. With that much ice collection the weight on tree branches can be enough to bow or snap them. Should the branches then contact power lines, that can lead to outages. The thicker glaze of ice also makes for hazardous travel with untreated surfaces becoming very difficult to navigate. The area of the Maritimes at most risk of that much freezing rain is central and western areas of New Brunswick. Ice accretion of 10 mm or more is associated with a severe ice storm. For this particular weather system, areas at risk of that much freezing rain include parts of the St. Lawrence River Valley in Quebec and the Ottawa Valley in Ontario.
