Numerous new wildfires burning in Canada are sending thick smoke into the skies of the United States (US). Several of the large wildfires in Quebec started last week (June 2nd), and are continuing the unprecedented start to Canada’s wildfire season due to abnormal dry and warm weather. Let’s take a look into the weather that caused these fires to spawn and spread, as well as who is affected by the smoke, and when it will end.

Location of Canadian wildfires and size/category of the fire courtesy of Natural Resources Canada. 

Several of the wildfires developed late last week on June 1st and 2nd. As of Tuesday, June 6th >100,000 hectares or >250,000 acres have burned. The causes of the wildfires are still unknown but are likely due to natural factors, and the weather leading up to and during it has certainly been a significant factor. 

These wildfires are very similar to the ones that I wrote about last week in Nova Scotia. A strong and persistent high-pressure system has remained stationary over Canada through the past couple of months, which has caused very little rain and well above-average temperatures. 

Average precipitation departures (mm) in the past 30-days with locations of the largest wildfires highlighted. This graphic is from the Government of Canada Agroclimate data. 

These precipitation departures in excess of 50mm (>2in) below the average just in the last month (May) have caused these wildfires to grow substantially due to the dry forests in Quebec. Once the fires started spreading, there was nothing stopping them from growing quickly. Gusty winds in excess of 40mph have helped fuel this wildfire and have transported smoke into the mid-levels atmosphere, and then into the United States. 

Why has the smoke traveled to the United States?

The low pressure system that dampened the wildfires in Nova Scotia is leading to wildfire smoke transport into the US. This storm system is stationary and spinning northerly winds from the Quebec wildfires into the US. Due to little movement of the low pressure, these winds have been consistently fueling the wildfires with wind transport all the way into the southern US states. 

OpenSnow surface smoke map forecast for Wednesday evening, June 7th. These maps go out hourly and forecast for up to 48 hours. 

The yellow streamlines (wind) around the Low pressure (red L) as indicated by the red arrow from the wildfires in Quebec.  

The National Weather Service has issued numerous Air Quality Alerts for code orange and red, meaning that “air pollution concentrations within the region may become unhealthy for sensitive groups.” I am not sure if I have ever seen so many Air Quality Alerts across the US before, let alone whole states. 

National Weather Service Warnings and Advisories map from June 6th, 2023. You can see the air pollution on the OpenSnow Air Quality Map, as well. 

New York City on Tuesday had the worst air quality in the world (>190 AQI), with air quality alerts extending to the southern US through Texas. What is also noticeable is the dry conditions in parts of the Northeast US, where a dry and warm spring has led to critical fire conditions. Several dry thunderstorms with lightning igniting wildfires are possible over the next couple of days, mainly in New Jersey and eastern Pennsylvania. If these wildfires ignite, smoke problems would worsen for Eastern cities. 

When will this end?

Unfortunately, the forecast does not look good for smoke to dissipate within the next week. The storm system off of Nova Scotia will keep spinning and remaining relatively stationary over the coming days, due to a weak and non-existent jet stream. This will keep northerly winds pumping smoke into the US and prevent any rain from putting the wildfires out. 

Looking past the weekend into next week on Monday, June 12th, a storm system will likely swing through the Great Lakes and extend moisture into the northern US and Canada. This storm system will change the winds and prevent smoke from entering the US and likely help wildfire fighting conditions. 

This period of rain will be short lived as another area of high pressure with dry and warm weather moves in by next late week, June 16th. The wildfires will likely continue to produce smoke, but it is hard to tell whether this will extend into the US this far out. Here is a look at the Climate Prediction Center’s temperature and precipitation probability from Wednesday, June 14th to Tuesday, June 20th.  

The above average temperatures and below average precipitation probabilities extend into areas of Canada as well. The wildfire season is just getting underway with no clear signs of widespread extinguishing within the next few weeks. Keep checking back on the News articles for more updates this summer. 

Also, be sure to regularly check our Smoke Forecast and Air Quality Maps for the latest conditions.

Zach Butler