The numbers I see nearest me match what I get on all my non-Alpha geiger counters for background radiation. My Alpha geiger counters always read more than double that. What types of sensors are being used? Is this from the same feed that windy.com uses?

If you click on a point you should see what tube they're using.

"use two fingers to move map"

WHY? Afaict the only thing that one finger drag is bound to, is an obnoxious message to use two fingers to do that.

I'd anyway be wary of placing fingers on a radiation map.

Like too many things like this posted online, I have no clue what I'm looking at and they're not about to tell you.

There is tutorial page https://www.gmcmap.com/tutorial.asp

Oh wait

"You do not have permission to access this document."

Odd, works for me. Maybe problems from the HN hug?

It probably doesn't have the information anyone wants though, as it's the tutorial to activate your device GC Electronics device to report to the site.

With counts so low, you're measuring a combination of altitude and the sensor's proximity to bedrock granite.

Putting a sensor in a truly hot spot, like a beach with thorium-enriched black sand would completely swamp the scale.

What's that bright red spot roughly in the triangle between Madison, Milwaukee, Chicago?

And another one below Osnabrück, Germany in Georgsmarienhütte?

What could cause this? Hardware error? Miscalibration?

Hrrm. Closed the tab and reloaded. 'Triangle' (Eagle Springs) back to normal, Georgsmarienhütte still RED, new one in Taipeh RED. Strange. Maybe software error? Or are the naturally occuring fluctuations that fast?

Hrrm. Letting it run for a while, refreshing itself. Taipeh back to normal, Georgsmarienhütte still red. Additionally Nebra(Unstrut), Germany red.

Don't know what to make of this. Seems 'wonky'?

The API is obviously open and you can submit your own readings which are not verified in any way. It is a good effort but I wouldn't trust all the data you see on this site.

That was the theory my 8 year old came up with - someone is having fun with a test source.

What's going on in Tuscon, AZ?

https://www.gmcmap.com/historyData.asp?Param_ID=5633273152

North Montreal, Charlemagne, Lachenaie is rather impressive also. Needs Log axis to print out the results visibly.

https://www.gmcmap.com/historyData.asp?Param_ID=17717804628

Spiked multi-thousand several times in the last couple days. Out of the last week, with ~2500 entries, ~500 > 100 CPM, ~20 > 1000 CPM.

Looks like they're in the middle of suburbia next to a mall. Maybe their neighbor bought uranium or something? However, also downstream of the city dump is what it appears, possibly somebody dumped something they should not have?

Also, would not have noticed the History Data printout otherwise, so thanks on that.

probably just a miscalibrated "tube"

there is a hotspot in peter jensen's house milwaukee too ... but alas not a stranger thing, likely just his thing is dirty.

No measurements in my home Normandy, where there is a dozen of active reactors?