Top ten weather stories for 2005: story six
6. April Showers Bring May Floods to the Maritimes
Several Nova Scotia communities experienced their driest summer on record in 2005. But before the dryness, they had to endure their wettest spring ever. At Halifax, spring rainfall from March to May inclusive totalled a record 589.4 mm - some 225 mm greater than normal. Of the total, more than half fell in May, drowning the previous record of 230.1 mm set in 1971. Other all-time May records this year included Cape Sable Island at 418.4 mm and Liverpool at 508.4 mm.
The mammoth rains came from a parade of storms moving up the East Coast and stalling over the Maritimes from a blocking ridge of high pressure over Labrador. The system that hung around from May 21 to 27 generated strong winds and most of the rain that led to major flooding across the Maritimes. The heavy rainfall on the long weekend in May caused many rivers and lakes along the south shore of Nova Scotia to flood, prompting officials in Lunenburg to declare a local state of emergency. Rising waters swamped homes, closed bridges and washed away several roads, leading to numerous evacuations. The wet May had an adverse effect on farming, delaying crop planting by two to three weeks. It is hard to imagine a more dreadful month of weather. Even when it wasn't raining, it was cold, grey, overcast and blustery. At Halifax, temperatures were 1.4°C cooler than normal, and only once in May did the day's high rise above 18°C. Total sunshine at Shearwater amounted to only 63% of normal for the month - some 70 hours short of normal. Even more revealing, over half the days had less than one hour of sunshine including nine days in a row.
Flooding was worse in the upper reaches of the St. John River in New Brunswick. The headwaters of the basin received heavy snowfall throughout the winter and record precipitation in March and April. Saint Leonard lost 151 cm of snow on the ground in five weeks. When the large accumulation of snow and ice started melting quickly, followed by heavy spring rains and some very warm temperatures the second week of May, the spring freshet came fast and was intense. Water filled the Saint John River to the brim. Then came the copious rains on the May long weekend with 80 mm at St. Leonard. Flooding forced more than 40 families from their homes and washed out major sections of New Brunswick's main highways and several city roads. At Fredericton, the river rose a metre above flood stage pushing water into streets and homes. While flooding was much higher than normal, it was still a half metre lower than the highest levels reached in 1973's one-in-200 year flood.
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