Continuity mistake: Just as Grandma jumps out of the boat you see Harry move towards her. You can see (and hear) his foot hit the bottom of the boat, when just before, it showed the boat almost completely full of acid.
Suggested correction: His pant leg to mid upper shin shows it's soaked.
Continuity mistake: The watch of one of the councilmen shows 1.40. (the stubby one in the white shirt, the one that tries to get the investor to invest in the city). Some 18 seconds later it shows 1.45.
Factual error: When being rescued from the crater, Harry tells the helicopter that he is 600 feet below the rim. But earlier, when first the other scientist and then Harry went down into the crater it took a very short time - that could not have been 600 feet. And also from the look of the distance it was more like 150 feet. (00:13:10)
Suggested correction: He's saying he's "about" 600ft below the helicopter, not below the rim. Also, Harry was just guessing at the distance, it could be more, it could be less.
Revealing mistake: While the scientists are trying to escape, Paul and his truck get tossed aside into the swollen river, but the truck is suddenly much smaller than it should be.
Other mistake: During the end-credits, someone's title is listed as 'Mr. Bronson's Driver' instead of Brosnan.
Other mistake: When Harry gets out of the truck at the motel to retrieve E.L.F., there appears to be a blue & white storefront sign in the background that is lit, when the rest of the town is dark due to no power. Either that, or it is a really bright, white, non-electric sign that has been completely unaffected by the ash that is coating everything else in town. (01:26:40)
Factual error: If the lake was already acid while the family was in the lodge for a while, the wooden docks should have already been dissolved.
Suggested correction: Different materials react with sulphur dioxide in different ways. Sulphur dioxide (or SO2) wouldn't actually dissolve wood, it would just char it and weaken it.
Continuity mistake: When they get in the boat to cross the lake, they notice dead fish floating on top of the water. On the other side of the lake, there are no dead fish.
Other mistake: When the lahar slams into the bridge, it seems strange that none of Paul's windows shatter while he's trying to get across. A lot of mud and debris slams into all three vehicles, but their windshields and windows remain intact. Also, the bridge entrance is washed away, but the rest of the bridge remains standing, until it tilts upward and disappears, taking Paul and his van with it.
Continuity mistake: After Terry falls in the crater, watch Harry climbing down to him. Harry is almost down, then the scene flashes to him at the top of the rim again, and he makes his way down a second time.
Revealing mistake: When Lauren screams after seeing the bodies in the hot spring, someone grabs her, but it is none of the characters in the scene.
Character mistake: When Harry is registering, he has glasses hanging around his neck and is wearing another pair, presumably readers, while he checks in. After exchanging pleasantries with the proprietor, he takes off the glasses, puts them on the counter, and leaves without them. (00:08:05)
