Cambridge, New Hamburg and Ayr were three of the communities believed to be most at risk of flooding in the Grand River watershed as of Tuesday evening.

Grand River Conservation Authority data showed that major increases in river levels began around mid-morning Tuesday. As of 5 p.m., the water was still rising in the Grand, Nith, Conestogo and Speed rivers.

At that point, water levels in West Montrose were high enough to flood the trailer park and come close to flooding the village. In Cambridge, Riverside Park, Bishop Street and Blackbridge Road were closed, as was the Galt-bound side of Blair Road.

A flood warning remained in place for the entire Grand watershed.

Water levels were expected to continue increasing into Wednesday as more rain fell on southern Ontario and water from higher in the watershed made its way downstream.

The Nith River was running particularly high, with flooding likely to extend past traditional low-lying areas. The GRCA said flows would likely peak late Tuesday night into Wednesday morning in New Hamburg, and about 24 hours later in Ayr.

In New Hamburg, 270 homes near the Nith had been warned that they could be affected by flooding. Wilmot fire chief Rod Leeson said “half a dozen streets” in the community would likely end up underwater.

Less certain was the forecast in the Grand River for Cambridge and communities further downstream. The existence of ice jams in the river made it more difficult to determine exactly how water would flow.

“The ice jam in Cambridge has still not moved downstream and there’s certainly a lot of ice building in Brantford and Cayuga as well,” GRCA spokesperson Cam Linwood said in an interview.

“We’re certainly keeping an eye on those areas.”

Flooding concerns also permeated local communities not considered part of the Grand watershed.

A flood warning was in effect from the Long Point Region Conservation Authority, with officials there warning of a strong flood threat to Tillsonburg and Vienna from Big Otter Creek.

The Saugeen Valley Conservation Authority said its entire watershed was under a flood watch, with water levels expected to rise into Wednesday and low-lying areas likely to flood.

A flood warning was also issued by the Upper Thames River Conservation Authority, which warned of potential flooding of Highway 2 in Woodstock, the Stratford Golf and Country Club, and other areas in Oxford and Perth counties.

Dozens of local roads were closed Tuesday due to flooded and washed-out roads. As of 6:13 p.m., the list included the following:

  • Blair Road in Cambridge, heading from Blair to Galt but not from Galt to Blair
  • Blackbridge Road in Cambridge, at the bridge
  • Thomas Street between Inglis and Elliott in Ayr
  • Main Street between Scott and Hall in Ayr
  • Conservation Drive between Beaver Creek and Erbsville in Waterloo
  • Three Bridges Road at the low-level bridge near St. Jacobs
  • Glasgow Street South between Waterloo and Conestogo
  • Misty River Drive between Glasgow and Flax Mill in Conestogo
  • The intersection of Tribe and Wollis roads, east of West Montrose
  • Lisbon Road east of Nafziger Road, outside Wellesley
  • Wilby Road between Nafziger and Sandhills in Wilmot Township
  • Carmel Koch Road between Nafziger and Sandhills in Wilmot Township
  • Perth Road 105 (Wilmot-Easthope Road) between Hutchison Road and Line 47, west of Wellesley
  • Milton Street between Shade and Hannah in New Hamburg
  • Berlett's Road between Nafziger and Sandhills in Wilmot Township
  • McLagan Drive, between John and Avon in Stratford
  • T.J. Dolan Drive between St. Vincent and Huron in Stratford
  • Perth Road 130 between Line 44 and Line 46, north of Stratford
  • Perth Road 116 between Line 80 and Buehler Line, south of Dorking
  • Perth Line 66 from Road 154 to Road 140, west of Milverton
  • Perth Road 147 north of Line 66, west of Milverton
  • Perth Road 154 from Line 71 to Road 72, northwest of Milverton
  • Perth Line 59 between Road 131 and Road 136, south of Milverton
  • Perth Road 140 between Line 44 and Line 42, northeast of Mitchell
  • Perth Road 155 between Line 42 and Line 46, northeast of Mitchell
  • Perth Road 150 between Line 26 and Line 29, southeast of Mitchell
  • Perth Road 167 between Line 89 and Perth Road 178, north of Listowel
  • Dundas Street between Ingersoll Road and 11th Line in Woodstock
  • Oxford Road 22 between Road 29 and Road 8, northeast of Innerkip
  • Oxford Road 19 between Oxford Road 13 and Middletown Road, west of Otterville
  • George Street South at Maitland Street in Harriston
  • Sideroad 5 between First Line West and Third Line West, west of Elora
  • 4th Line between Wellington Road 50 and Side Road 10 in the Town of Erin
  • 3rd Line between Side Road 5 and Side Road 10 in the Town of Erin
  • Station Road between Trafalgar and 6th Line in the Town of Erin
  • Wellington Road 18 between Line 86 and the community of Salem
  • Sixth Line north of Wellington Road 50, east of Rockwood
  • Seventh Line between Sideroad 20 and Wellington Road 22, northeast of Guelph
  • Fourth Line between Wellington Road 124 and Sideroad 20, northeast of Guelph
  • Third Line between Sideroad 22 and Wellington Road 22, northeast of Guelph