@bobbok ….the Guardian really, that bastion of honesty? But once again the experts have found what they want to find. Here’s a history of exceptional heat and glacier failure and Chat’s well reasoned conclusions.
………
Yes. The sanity check weakens any simple claim that “major glacier collapse = exceptionally hot weather”.
Looking at the better-documented failures:
Event Immediate temperature/weather evidence Does exceptional heat look important?
Altels, Switzerland — Sep 1895 Contemporary observers specifically described 1895 as warmer than usual, and later modeling found that warming and meltwater could have reduced basal adhesion. The paper also notes several unusually hot preceding summers. Probably contributed
Kolka, Caucasus — Jul 1902 Historical evidence identifies major ice/rock falls and glacier instability, but I could not find a reliable quantitative temperature anomaly for the preceding days/weeks. Unknown
Huascarán, Peru — Jan 1962 A true ice avalanche occurred, but classic glaciological reviews explicitly say how the simultaneous failure occurred remained an open question. Not established
Allalin, Switzerland — Aug 1965 Glacier was in one of its recurring surge-like active phases. Meltwater was involved, but these active phases occurred every 1–3 years without catastrophic failure. The literature does not identify exceptional heat as the decisive trigger. Possible, not demonstrated
Huascarán — May 1970 Triggered by a M7.9 earthquake. No
Kolka — Sep 2002 Complex rock/ice collapse preceded by weeks of rock and ice falls. Researchers considered many mechanisms; the source zone was actually cold permafrost, estimated around −5 to −10°C. No clear exceptional-heat trigger
Aru-1, Tibet — Jul 2016 Nearby station data showed temperatures within the normal range; NASA explicitly says there was nothing unusual about temperature or rainfall. Another study did find unusually high precipitation. No
Aru-2, Tibet — Sep 2016 Same regional situation; researchers emphasize unusual glacier dynamics, basal conditions and mass balance rather than a short heatwave. No clear heat trigger
Chamoli, India — Feb 2021 About a +5 K temperature anomaly during the preceding week, plus heavy snowfall. But the detailed study says the proposed meteorological triggers lack a strong demonstrated mechanical connection and temperatures at ~5,000 m remained below freezing. Plausible, uncertain
Marmolada, Italy — Jul 2022 This is the strongest case: preceding 70 days had temperatures outside the 1990–2020 standard-deviation range and at record highs; excess meltwater produced high hydraulic pressure. Yes, strong evidence
Nepal–Tibet — Aug 2026 Ground temperature measured ~10 km away was reportedly the highest in the two-year sensor record, two days beforehand. Cause remains under investigation. Plausible, too early
What I think the sanity check tells us
Of the roughly 10 historical cases for which we have something useful to say, I would classify them approximately:
2 with fairly strong evidence of unusually high temperature: Altels 1895, Marmolada 2022.
1 with a substantial short-term warm anomaly but uncertain causation: Chamoli 2021.
2–3 where ordinary meltwater/summer conditions mattered but extraordinary heat has not been demonstrated: Allalin and perhaps Kolka.
Several where exceptional heat is absent, unsupported, or clearly not the trigger: Aru 2016, Huascarán 1970, and probably others.
And Aru is particularly valuable as a control case: two enormous glacier detachments occurred in the same summer, yet measured temperatures were not exceptional.
That leads me to revise the weight I'd put on the current 2026 heat observation. The fact that the collapse occurred during warm August weather is not particularly probative, because glacier failures are already disproportionately summer/melt-season phenomena. And saying the nearby ground temperature was the highest in a two-year record sounds impressive, but two years is far too short to establish that the weather was historically exceptional.