The aftermath of a nasty Christmas storm is subsiding across Southern Ontario, but it might be subsiding a bit too quickly, as a one-two-punch of warm temperatures and rain substantially increase the risk of flooding across the region.

Over 16 cm of snow has descended upon Toronto since mid-December, accompanied by frigid temperatures as low as the negative double digits that have so far prevent major melting.

But, as of Thursday, the mercury has soared into the high single digits and threatens to crack double digits by Friday. And the melt has already begun.

A system of precipitation is also moving towards the region, expected to arrive by the weekend, and the combined effects of the warm air temperatures and rain have Environment and Climate Change Canada warning of potential flooding in waterways across the region.

⚠️Significant temperature rise this week
Temperatures could reach 10 degrees Celsius on Friday for many places in S Ont.
The warm air will lead to snow melt. Rain is also likely this weekend.
Forecast 👉 https://t.co/oZeNuI30mX
Image courtesy @WeatherBell #ONWx #ONStorm pic.twitter.com/yoBE7FA8CV

— ECCC Weather Ontario (@ECCCWeatherON) December 28, 2022

The government weather agency warns that "rapid snowmelt when the ground is still frozen can cause flooding even in areas that have not flooded before," adding that "proper draining, even in winter, is important to reduce property damage."

🌡️ Warmer temperatures are arriving over southern Ontario. Rain is also expected. 🌧️

Forecasts: https://t.co/KaVXMA1KUn

Ontario Ministry of Natural Resources and Forestry flooding information: https://t.co/1cKag1PzLT#ONwx #ONflood pic.twitter.com/zKSDEnk9wX

— ECCC Weather Ontario (@ECCCWeatherON) December 29, 2022

The coming band of rain could bring as much as 25 mm to the Greater Toronto Area, according to The Weather Network, while even higher rainfall totals of 30-44 mm are predicted for southwestern Ontario.

Melting snow and the approaching system have already combined to trigger flood watches in Niagara Region.

A Flood Watch has been issued by Niagara Peninsula Conservation Authority. https://t.co/JKjMVkEyJG pic.twitter.com/F7Lea6jk7u

— NPCA (@NPCA_Ontario) December 28, 2022

A flood alert was issued by the Niagara Peninsula Conservation Authority on Wednesday, while a region-wide alert followed on Thursday from The Weather Network, cautioning of localized flooding in waterways as mild temperatures, rainfall, and ice jams join forces.