June 30, 1908 was the date of the Tunguska impact. A 220-million pound (100 million kg) meteor exploded over an isolated area of Siberia - an estimated 80 million trees were simply blown over by the blast. There were few close witnesses, and scientists (and others) didn’t reach the area until 19 years later. Possibly the largest natural explosion in recent recorded history, although Krakatoa competes for the number one spot.
Selected pages from a book on the subject:
Not only that, it was the biggest inter-dimensional cross rip in history until Gozer the Gozerian showed up in NYC in 1984.
Excuse me, they want a sample of my brain tissue.
Do you collect molds, spoors and fungus?
Speculation: lets say this hit over a larger populated area. What changes in society do you think this would have caused?
I know SDMB protocol is tomdisregard typos and mis-spellings, but this one KILLED me!
“spoor” is poop, typically the stuff you find when tracking game animals.
“spores” are “mushroom seeds.”
But I guess there are folks who collect spoor…
~VOW
Add this to ^^^above post^^^ 
~VOW
Well, there’d be a lot less of society if a meteor cooked off over a populated area. I don’t think there’d be much of a change in civilization; we collectively survived the last one (112 years ago), and we’ll collectively survive the next one should it happen again. With a freak occurrence like that, there’s not much you can do, other than keep scanning the skies in hopes of having some warning.
. . . unless maybe society wants to organize a diplomatic peace envoy to Klendathu.
Tripler
Heck, maybe they’ll re-fund the SETI project!
For round numbers it flattened an area 30+ miles across, 15+ miles in radius. So a decent-sized modern city + inner suburbs. Or substantially an entire 1908 metropolis & surrounding nearby larger towns.
In other words, it’s comparable to a modern strategic nuke.
If it hit a capital city I’d expect that nation would have needed a completely new government. And it may have been annexed by aggressive neighboring nations before that could be arranged.
For sure (kinda like this classic Raindrop), folks would be nervously eyeing the sky for a few years afterwards.
Of course certain religions would say this vindicates their prophesies of their god whacking those baddie infidels who totally deserved it. Unlike us goodies who were carefully spared.
Big picture, this isn’t going to vastly alter civilization as such. It would alter many smaller specifics and due to the butterfly effect might have completely changed, e.g. WWII.
From the OP’s first link:
At 7:17 a.m. (local Siberia time), at a height of about 28,000 feet, the combination of pressure and heat caused the asteroid to fragment and annihilate itself, producing a fireball and releasing energy equivalent to about 185 Hiroshima bombs.
Little Boy was ~15 kt yield. Tunguska was therefore 15 kt * 185 = 2.775 Mt. Just a touch larger’n yer average modern strategic nuke.
Tripler
I yield to the rest of the discussion.
Quite right. Good catch. And you’d sure be the guy to catch it.
I’d forgotten we’ve retired all the B53s (9MT yield) by 2011. They were in the inventory longer / later than I was. Now we’re down to the comparative pipsqueek B83 (1.2MT) as the biggest. For darn sure from 1960 to today the trend has been down in yield and up in accuracy. I’m not so sure other nuclear powers have followed quite the same yield curve we have.
In any case a 2.5-3.0 MT airburst would sure trash any 1908 city. Although in the case of a meteor burst you’ll have all the overpressure without (much of) the heat wave and none of the radioactivity. So a much better post-burst situation for the survivors.
But still likely to start a pretty good firestorm vs. 1908 firefighting tech. cf. 1906 San Francisco earthquake - Wikipedia
Just for gee-whiz, I ran an open-source, unclassified ‘shot plot’ on a nearby city. It ain’t pretty.
But LSLGuy, you are correct; you don’t have to deal with radioactive fallout. The unpredictable variable is fragmentation–just like conventional ordnance, if the blast overpressure doesn’t catch you, the fragments of that piece of ordnance can bite you in the arse. I’d have to do the math for hazardous fragmentation radius, but back-‘o’-the-envelope math to me says that anyone walking outside within a 25 mile radius ought to have a steel umbrella.
Tripler
. . . or Kevlar boxer shorts.
And yet, all the recovered suspected fragments of Tunguska wouldn’t fill a thimble.
I betcha there’s Tunguska chunks scattered all over the place, and they rained down far outside of the surveyed blast pattern. Spitballing here, but meteors are not of predictably-homogeneous construction like military ordnance; there could be faults, fissures, and chunks of foreign material within the composition of the meteor itself–kinda like lumpy oatmeal iron and nickel–which would heat differently and produce non-homogenous fragmentation.
Tripler
Ain’t science fun?!?? 
No comment. I’m disregarding both the typo and the misspelling.
The most amazing thing about a meteor (that doesn’t hit you) is you’ll hear this amazing whooshing noise as it goes by overhead. 
That url is set for ground burst. And an impressive ground burst it is. A real crowd-pleaser as we used to say.
I played w air bursts at various altitudes, and switched off the radiation rings as irrelevant.
For max blast overpressure (again with a nudet, not a meteor) the biggest damage area comes from a relatively low burst at ~4km / 12k ft altitude. That damage area dwarfs the ground burst damage area as they usually do; ground bursts waste a lot of energy overkilling the point of impact. Unneeded unless you’re digging up hardened shelters. Far better the share the wealth more widely.
Wiki suggests Tunguska blew at 5-10km which would be in the ballpark for maximizing the blast radius Although the article is unclear about which factors are known, which are assumed, and which are solved for.
Chelyabinsk was a vastly smaller bolide than Tunguska with energy deposition ~400/500Kt equivalent. And it’s known to have broken up / burst at 30km / 100k ft. Much higher.
I don’t know whether something Tunguska sized would be more prone to holding together deeper into the atmosphere or more prone to breaking up sooner. Bursting Tunguska at 100K ft is almost a non-event on the ground blast-wise.
But as you say, overpressure or no, it’d be a shotgun pattern of ~100K tonnes of high temperature rock and/or iron. All else equal I’d rather be uprange. Brass 'nads and kevlar underoos notwithstanding.
Now, see, I wouldn’t even get the fun from that. My hearing is crappy. Actually, it’s not even good enough to rate crappy.
I bet the breeze would be awesome!
~VOW
There is evidence that the 1871 Chicago fire was actually caused by a meteorite. It broke out in several areas at once, and that same night was the “spontaneous” forest fire that nearly destroyed Peshtigo, Wisconsin, and people on ore boats in the Great Lakes saw, as they described it, fire falling from the sky.
I would actually have been more concerned about something like this happening over the ocean, where it could have created a megatsunami.
Playing around with the NUKEMAP site, a 2.775 megaton airburst at 5 kilometers altitude would cause “moderate” damage (5 psi overpressure) for a radius of 6.81 km. “Moderate” damage is defined as
Light damage (1 psi overpressure) would extend out to 28.8 km. Light damage would include
At the high end of the range given upthread for the altitude of the Tunguska detonation (10 km) you apparently wouldn’t get any 5 psi overpressure on the ground; you would get light blast damage (broken windows and the like) for a radius of 21.1 kilometers.
I didn’t do any of the thermal effects, because I don’t know how asteroids and/or comets compare to thermonuclear explosions; I presume the thermal effects of an explosion the size Tunguska weren’t zero, but I don’t know if there would be any thermal damage at ground level from those altitudes.
Bottom line, at the low end of the range for altitude, Tunguska would definitely have wrecked a good-sized city.
Whoops! My mistake. It’s been a long day/week. My weaponeering is off this week. 
Tripler
Take off and nuke it from orbit–it’s the only way to be sure.