Triple-Digit Record Heat Peaks in the Rockies and West: A Super Simple Explainer

What’s Going On? (The Big Picture)

Imagine a giant invisible lid in the sky called a heat dome. This lid traps hot air close to the ground, like a blanket that won’t let the heat escape. This weekend, that lid kicked off and broke temperature records in the northern Rocky Mountains and the Northern Plains (the northern central US).

Now, that hot and sticky air is going to travel:

• It will spread to the Midwest later this week.
• Then it will reach the East Coast.

Important Callout: This heat can make people very sick. Always take heat warnings seriously!

National Parks That Will Be Hot

If you are visiting these parks this weekend, pack for surprise heat! The heat wave will hit many national parks, including:

• Glacier
• Yellowstone
• Grand Teton
• Badlands
• Theodore Roosevelt
• Utah’s "Mighty 5" parks (a group of five parks in Utah)

Even if you expect mountains to be cool, it might be much hotter than you think.

What Is a Heat Dome? (Quick Explain)

A heat dome is like a huge bubble of high pressure in the atmosphere. It pushes warm air down and stops clouds and rain from forming. The result: day after day of strong sun and trapped heat.

Rockies and Northern Plains Forecast

Heat Alerts: Watches and Warnings

Right now, extreme heat alerts stretch from the Rockies to the Midwest, including parts of the Dakotas and Minnesota.

• Extreme Heat Watch: This is given when the weather conditions could cause a dangerous heat event in the next 24 to 48 hours. This heat could make people sick with things like heat exhaustion (feeling super weak and overheated) and heat stroke (a dangerous condition where the body overheats).
• Extreme Heat Warning: This is issued when those hot conditions are definitely going to happen.

If a warning is issued, here are the steps to stay safe:

1. Stop all big outdoor activities (like hiking or sports).
2. If you don’t have air conditioning (AC), find the nearest cooling shelter (a place with AC open to public).
3. Or make a plan to stay with family or friends nearby who do have AC.

Important Callout: Don’t wait until you feel sick. Plan ahead when a warning is announced!

How Hot Will It Get?

Through the middle of the week, these areas will be baking:

• Parts of Utah, Idaho, Wyoming, Colorado, Montana, and the Dakotas will see daily high temperatures (the hottest time of day) in the upper 90s°F and even over 100°F (triple digits).
• In some bigger cities, the temperature at night (morning lows) might not drop below 70°F, so no cool break.
• A little bit of relief may come to some of these places by mid-week.

Could All-Time Records Fall?

This isn’t just about breaking a record for one day—some places might hit the hottest temperature they have ever recorded.

• Salt Lake City is trying to reach its all-time record of 107°F. That record was set on five different days, most recently on July 17 and September 7, 2022.
• Billings, Montana might hit the 110s°F for the first time in 92 years of record-keeping (records go back to 1934).
• Almost two dozen locations in eastern Montana and Wyoming could also tie or beat their own all-time hottest highs.

Midwest and East Forecast

When Will the Heat Arrive?

Think of the heat like a slow-moving wave:

1. The upper Midwest (especially Minnesota) felt it first.
2. By Monday, the hot, humid air will slide through the rest of the Midwest.
3. By Tuesday, it reaches the East.

How Hot Will It Be There?

• Many areas will see afternoon temperatures in the 90s°F.
• A few spots in the Midwest and East Coast might get close to 100°F around the middle of the week.
• Daily records could be broken on Tuesday and Wednesday in parts of the Northeast: New England, upstate New York, and the mid-Atlantic states.
• In larger cities, nighttime lows may stay in the middle or upper 70s°F, so evenings stay warm and uncomfortable.

Important Callout: America’s deadliest weather is heat, not tornadoes or hurricanes. Treat this carefully!

When Will Relief Come?

Good news: a fairly strong cold front (a moving boundary of cooler air) might drop down from eastern Canada into the Northeast on Tuesday into Wednesday.

• That could bring cooler air from the northern Great Lakes to New England by mid-to-late week.
• But it might also cause strong thunderstorms with damaging winds (winds that can break branches or fences) ahead of the front.

Summary

A heat dome is causing record-breaking triple-digit heat in the Rockies and Northern Plains, hitting national parks like Yellowstone and Glacier. Heat watches and warnings are active; if a warning is issued, cancel outdoor plans and find AC. The heat will spread to the Midwest by Monday and the East by Tuesday, with temps in the 90s and near 100°F. Some places may break all-time heat records. Relief may come mid-week for the West and via a Canadian cold front for the Northeast, but storms may tag along.

FAQ

1. What is a heat dome in kid terms?
It’s like a giant lid in the sky that traps hot air near the ground, making it super hot for many days.

2. What should I do if a heat warning is issued?
Stop outdoor activities, and if you lack AC, go to a cooling shelter or stay with someone who has AC.

3. Which national parks are affected by this heat wave?
Glacier, Yellowstone, Grand Teton, Badlands, Theodore Roosevelt, and Utah’s "Mighty 5" are among those hit.

4. When will the East Coast feel the heat?
The hot air is expected to reach the East by Tuesday.

5. How can I stay safe without air conditioning?
Find a public cooling shelter, or arrange to stay with friends or family who have AC. Also drink water and avoid the sun.