More than 300,000 students across Toronto will wrap up their schooling for 2022 with a snow day Friday as a wicked winter storm looms over the city.

"With widespread blowing snow, damaging winds, poor visibility, and flash freezing currently being forecast for tomorrow and into the weekend, we have made the decision, together with the Toronto Catholic District School Board, to close all schools, administrative buildings and sites to students and staff tomorrow," the Toronto District School Board (TDSB) said in a message to parents and guardians sent just before 3 p.m. on Thursday.

There are some 235,000 students enrolled in TDSB schools and another 92,000 in the city's Catholic system, and the move will send parents and caregivers scrambling to make alternate arrangements.

"We recognize that these decisions can have a significant impact on thousands of families across Toronto and are not taken lightly," the TDSB said. "(H)owever, given the current weather forecast, we felt it was prudent to make this decision now to provide families and staff with as much notice as possible."

Environment Canada has issued a warning that travel will become hazardous as rain or snow starting tonight will be joined by wind gusts of up to 90 km/h on Friday, reducing visibility to zero and creating frigid wind chill conditions and icy surfaces.

The TDSB said child-care centres and before-and-after school programs at their schools will be closed and all permits to use school facilities, continuing education classes and evening courses are also cancelled.

The TDSB note also reminded students to take home any belongings needed over the winter break.