What atmospheric conditions would be needed produce intense heat, weather and wind that could fry a human in less than 5 minutes at sea-level? [closed]

Question

first time poster here.

The premise: I’m trying to design a planet in where sea-level / lowlands are an uninhabitable wasteland with temperatures that would fry a human in less than 5 minutes. In my mind, I’m imagining this area would look like an ash ridden area with intense winds and severe weather. This would be in contrast to highland areas (mountains, plateaus, and so on) which would have a more temperate climate.

Research: I am not a science guy, so a lot of the atmospheric stuff takes me a bit to grasp. I found a video https://www.youtube.com/watch?v=9-j_JOWPLj8 that kind of outlines a possibility by upping the atmospheric composition to feature 1% Co2, but I’m not sure if this would produce the exact conditions I’m looking for.

The question: What atmospheric (or planetary) conditions would be needed produce intense heat, weather and wind that could fry a human in less than 5 minutes at sea-level? I’m particularly interested temperatures, and possible composition (natural or otherwise), and containing it to sea-level/lowland areas.

And as a follow up question, would these kinds of conditions also prevent bodies of water from forming (and negating a water cycle)? Ideally, I would want to maintain a water cycle even if the oceans/bodies of water were not habitable.

A possible note to consider: the conditions would not necessarily need to be natural, but could be a result of technology, terraforming, or other artificial means.

Thanks for any feedback!

EDIT: Hello all, thanks for the all the comments. Right, I should have been more clear with the language. 'fry' in this case would be 'kill, and burned beyond recognition (hair gone, charring/skin burned away.)

Answer 1

Higher atmospheric pressure.

Here is a fine simple calculator, for earth of course. You enter the elevation and get back variables like temperature, atmospheric pressure, and air density. I modelled the effect of higher atmospheric pressure by giving the calculator negative altitudes.

https://aerotoolbox.com/atmcalc/

In the middle is 0 m elevation. Temp is 15C and pressure 101325 Pa as it should be.

On the left is -10000 meters. It is hot down there at 80C and not because of hot lava. Pressure is 295137 so roughly triple sea level, and air is 2.3 times as dense. On the right I entered +10000 meters. It is -50C and atmospheric pressure is about 1/4 of sea level. 10000 meters is Everest peak and those numbers are similar to pressure and temperature there so this calculator is reasonable.

On this planet sea level is equivalent to -10000 m elevation on earth. 10000 m elevation on Planet Hotness is the same as sea level on earth.

An earthlike planet (as regards solar energy received) with more atmosphere would be hotter in the lowlands. 80C is not boiling but not ok for any kind of terrestrial life. You would definitely have a water cycle because the oceans would be evaporating like mad. 100% humidity and 80C at 3 atmospheres is an autoclave. No Air Force volunteers gamboling about in their skivvies. Sorry @A Rogue Ant - those volunteers will have to appear in a different answer. Tell them to be patient.

Answer 2

If a temporary condition is acceptable, one only has to look at the Pacific Coast of the United States for a really good example of natural ambient conditions that will kill a human in minutes, or even seconds:

The basic recipe is a semi-arid climate region with a mix of very wet and very dry seasons, that encourage foliage growth in spring while making the landscape a tinder box in the summer and early fall. There are other elements at play in the current California wildfires (some blame climate change for hotter, drier, windier conditions, others blame mismanagement of forested land and an overemphasis on fire prevention leading to historic overgrowth), but it's not hard to invent a combination of fast-growing foliage and prevailing weather conditions that makes these fires so inevitable and unstoppable that humans either avoid the hazard or adapt their homes and equipment to tolerate it (as long as they're not out in it unprotected).

Answer 3

Charring and burning are almost certainly out if you want a semi-continuous situation.

You can have vegetation capable of sustaining very hot flash fires - large, juicy plants with dandelion-like flowers. Some (enough) of those flowers ripen and dry, resulting in a plain covered with fluff-like tinder which will go up in flames at terrifying speeds. It will burn hot, but not last enough to do real damage to the plants, which will then ready the next series of flowers. This way, you get a fire flash every few days.

A lower temperature (still lethal) can be achieved for longer periods if the air pressure is high enough and the terrain is favorable. Large masses of air are pushed towards the mountains, where they shed their humidity before falling in on the other side and compressing. On Earth this phenomenon gives rise to the Foehn, a hot wind. With more air in the equation, higher temperatures are possible; not enough to air-fry someone, but kill and desiccate, that is doable.

Answer 4

Flood Basalt

To achieve the effects you are describing purely through atmospheric conditions you risk a runaway greenhouse effect and the oceans would evaporate making the entire planet uninhabitable. You could make low lands unbearably hot with flood basalts. A flood basalt is thousands of miles of volcanic activity that lasts for millions of year. The ground itself would be extremly hot and thus heat up the air.The air would have all kinds of greenhouse gases, and ash making the place even hotter and less hospitable. To make it even more intense I would recomend loosly basing it of of the Central Atlantic Magmatic Province (CAMP). CAMP is the largest flood basalt to ever mark the planet, but it was also smack dab in the center of a super continent which makes it even worse. The oceans regulate temperature so being in the center of a super continent would already create very hot conditions. The moutains your characters live on can be on the coast which would give them ample percipetation to support their society. If the super continent is centered on the equator, That would further increase the in land temperatures and create very strong wind inland which should keep the air in the mountains breathable and give you those strong winds you asking for.