Tim Raupach

abc.net.auGiant, spiked hail falls as 'very dangerous' storms hit QueenslandSpiked hail stones have been observed at Mudgeeraba as "very dangerous" storms hit an already soaked south-east Queensland.

Amazing spiky hail fell in SE Queensland yesterday. It's like a ninja star made of ice. www.abc.net.au/news/2026-10...

The UNSW Institute for Climate Risk and Response annual conference is today. Admiral Chris Barrie, co-founder of the Australian Security Leaders Climate Group, opened with an incredible keynote calling for real action - with ownership and accountability - on climate security.

#ICRRForum2026 #ICRR #ClimateRisk

abc.net.auStorms 'swirling like a tornado' leave trail of destruction in parts of NTCentral Australian businesses and residents are assessing damage from severe storms that have swept through parts of the Northern Territory.

Golfball size hail in central Australia yesterday. Unusual but can happen. www.abc.net.au/news/2026-10...

theconversation.comWe can finally measure the damage each new coal, gas or oil project will do to people and natureFor decades, we couldn’t trace the link between new fossil fuel projects and their damage to people and planet. But now we can.

Carbon Impacts Tracer (carbonimpactstracer.com) traces carbon emissions from individual projects to quantified impacts across eight areas, including heatwave deaths in Europe. The makers explainer is here: theconversation.com/we-can-final... @sarahinscience.bsky.social @wesmorgan.bsky.social

nature.comThe worst El Niño in recorded history is brewing — here’s how governments must prepareFrom southern Africa to the Amazon, the risks are mounting and the window for action is rapidly closing.

@zekehausfather.com on how governments should be preparing for the coming El Niño that has a forecast >90% chance of being the strongest on record www.nature.com/articles/d41...

nature.comIncreasing LGBTQIA+ inclusion in climate scienceNature Climate Change - LGBTQIA+ climate scientists have long encountered oppression and discrimination across society and in the workplace. We suggest specific actions, which need to be supported...

22 Sept

Respect and applause to @andrewkingclimate.bsky.social, @alexborowiak.bsky.social, Ruchit Kulkarni, @drkimclimate.bsky.social, @taimoorsohail.bsky.social, Gen Tolhurst, & Anna Zehrung for this piece on making climate science more inclusive for LGBTQIA+ scientists 🌈 www.nature.com/articles/s41...

unsw.edu.auRegional hail properties for site-optimised solar modules

21 Sept

Interested in doing a PhD related to hail, microphysics, and solar energy? See this opportunity and apply by 30 November! www.unsw.edu.au/research/hdr...

Tim Raupach reposted

Andrew B. Watkins

@windjunky.bsky.social

14 Sept

My latest for the Conversation - a year on from the release of the NCRA, so what do we have to show for it (TL:DR not much). We have to do better, because we know the future we face. theconversation.com/its-been-one...

theconversation.comIt’s been one year since Australia assessed its national climate risk. But have we listened?Over the past 12 months, the federal government has approved multiple fossil fuel projects and cut climate science funding.

8 Sept

What a reassuring energy company I have. It's September - but hey, although winter is (apparently) here, big bills don't have to. They should make this their slogan.

Tim Raupach reposted

youtube.comHailstorm cancels Vuelta stage as riders seek safetyYouTube video by SBS Sport

On Monday, stage 3 of La Vuelta a España, the cycling race, was cancelled after a hailstorm forced riders to take cover and left hail covering the road. Let’s take a look at what happened! www.youtube.com/watch?v=ddn7... 1/14

abc.net.auSatellite images reveal giant scar left after glacier snaps in NepalClimate scientists have been warning that the Himalayas are warming faster than the rest of the world, increasing the chances of a disaster of this scale.

This visualisation of satellite imagery shows well the scale of the glacier collapse and/or landslide that caused the flash flood in Nepal. www.abc.net.au/news/2026-08...

nytimes.comClimate Change Raises Risk of Disasters Like Nepal Floods (Gift Article)Glaciers and permafrost in the Himalayas are melting faster as temperatures rise, though scientists are still studying the exact causes of this week’s landslide.

Devastating scenes from the terrible flood in Nepal. There will be lots of complex causes for this individual event but it does raise the question of whether mountain destabilisation is accelerating. www.nytimes.com/2026/08/27/c...

youtube.comHailstorm cancels Vuelta stage as riders seek safetyYouTube video by SBS Sport

And Zhang et al. (www.nature.com/articles/s41...) projected increasing hail damage potential in general, but a locally varying signal in southwest Europe with both increases and decreases across the Pyrenees region. 13/14

nature.comRising global hail damage potential in a warming world - NatureHailstone trajectory simulations conducted under historical and future scenarios show a shift towards larger hailstones, resulting in global hailstorm-induced damage potential increasing by around 40%...

These kinds of events highlight the damage and disruption that hail can cause, and put more focus on our ongoing work to better understand how these complex events may change as the climate warms. 14/14

youtube.comHailstorm cancels Vuelta stage as riders seek safetyYouTube video by SBS Sport

For example, for frequency of very large hail (over 5 cm), Battaglioli et al reported an increasing trend in Europe from 1950—2023 (www.nature.com/articles/s41..., CC-BY-4.0). 11/14

Future hail projections remain highly uncertain. For hail frequency changes with global warming, our recent work showed a general poleward shift in hail conditions, but no significant projected changes over the Pyrenees (adapted from www.nature.com/articles/s41..., CC-BY-4.0). 12/14

youtube.comHailstorm cancels Vuelta stage as riders seek safetyYouTube video by SBS Sport

It’s important to keep in mind that actual hail is usually highly localised within larger hail-prone regions, and hail-prone environments often do not produce any hail at all! That's because even the most hail-prone environment requires a storm to be triggered before you can get hail. 9/14

What about climate change? This is a hail-prone region so storms like this are not unusual in summer. We also can’t say any one storm was “caused” by climate change. But we can test whether storm environments are changing over time, and if storms are getting more or less frequent or severe. 10/14

youtube.comHailstorm cancels Vuelta stage as riders seek safetyYouTube video by SBS Sport

So was there instability and wind shear in this case? Yes, at least in the vicinity, in a model forecast (adapted from charts.ecmwf.int, CC-BY-4.0). 7/14

The European Severe Storms Laboratory’s more sophisticated forecast also showed probabilities of up to 60% for large hail, in regions around where the hail occurred (www.stormforecast.eu). 8/14

youtube.comHailstorm cancels Vuelta stage as riders seek safetyYouTube video by SBS Sport

Hailstorms are small in scale, so it’s hard to forecast or model exactly where and when hail will happen. But we can consider whether the atmosphere is more or less likely to produce hail. 5/14

We often consider the atmospheric “ingredients” for hail. Two common ones are instability (propensity for updrafts to form) and wind shear (difference in wind by height). If you have lots of instability and wind shear together, hail is more likely and the environment is “hail-prone”. 6/14

youtube.comHailstorm cancels Vuelta stage as riders seek safetyYouTube video by SBS Sport

The hailstorm hit when the riders were 15 km from the stage finish, cycling through Mont-Louis, at about 17:30 CEST (15:30 UTC). Radar data at that time show high reflectivities (over 50 dBZ) indicating the presence of large particles and lots of rain (zoom.earth/maps/radar/#...). 3/14

Some protruding clouds appear in satellite imagery at that time, likely developed by strong updrafts that can support hail growth (MTG GeoColour RGB with MSG IR10.8 in the background, view.eumetsat.int). 4/14

youtube.comHailstorm cancels Vuelta stage as riders seek safetyYouTube video by SBS Sport

The storm was in the eastern French Pyrenees. This region is no stranger to hail — the Pyrenees is a well-known hail hotspot. This map shows where we get the most frequent hail environments in Europe (www.nature.com/articles/s41... CC-BY-4.0). 2/14

nytimes.comSee How Nepal’s Flash Floods Caused Widespread Destruction (Gift Article)Floodwaters swept away villages near the border between Nepal and the Tibet region of China.

Terrifying scenes from this awful flood in Nepal and Tibet. www.nytimes.com/interactive/...

The New York Times@nytimes.com

The deadly flooding in Nepal on Wednesday was likely set off at least in part by an enormous chunk of ice snapping off a glacier and cascading thousands of feet to the valley below, according to an initial assessment by a group of geologists and glaciologists.

nyti.msDeadly Nepal Flood May Have Been Caused by ‘Ice Avalanche,’ Scientists SayAn initial assessment of satellite imagery suggests an “ice avalanche” from a high-altitude glacier sent a giant cascade into the valley below.

theguardian.comShould you use AI for a task? Here’s a simple way to decide | Bruce SchneierSometimes, what matters isn’t your output but what you put into the process. Think of it like work v the gym

11 Aug

This is good. Should you use AI for a task? Bruce Schneier suggests considering whether the task is "work" or "gym". www.theguardian.com/commentisfre...

rmets.onlinelibrary.wiley.comDamaging Surface Hail in Simulations of Satellite‐Detected Hailstorms in Australia's TropicsSatellite detections of hail signatures are uncertain in the tropics, where the deep troposphere increases the chances that ice detected aloft will melt before it reaches the surface. We used numeric....

7 Aug

In this new paper with Sarah Bang and John Allen, we used simulations to examine satellite hail detections in the Australian tropics. Roughly 1/4 of the simulations produced damaging hail at the surface. 1/4 rmets.onlinelibrary.wiley.com/doi/10.1002/...

Uncertainty remains, but these results show that at least a subset of satellite detections could correspond to damaging surface hail in this region. Read the full paper open access here: rmets.onlinelibrary.wiley.com/doi/10.1002/... 4/4

7 Aug

@ccrc.bsky.social @21stcenturyweather.bsky.social 👋

Hail in the tropics has high uncertainty. It occurs, but rarely, and observations are sparse. Satellite data often indicate hail signatures in the tropics, but these can be ice aloft that melts before it reaches the ground. So we tested how often this happens using simulations. 2/4

7 Aug

Differences between hail/no-hail cases are explained by entrainment theory. Hail cases had more shear to produce wider updrafts, and more humid surroundings. Together this led to less updraft buoyancy dilution and more realisation of instability into vertical motion, supporting large hailstones. 3/4

4 Aug

It’s great to be in Fukuoka for #AOGS2026. For this Sydneysider, experiencing WBGT over 34C also really puts heat-stress projections into perspective.

3 Aug

Still amused at atmospheric science journal proofs coming back with "reanalyses" - as in the plural of reanalysis - changed to "reanalyzes".

19 July

Just spent a wonderful week visiting Uluṟu and Kata Tjuṯa on Anangu land. Peaceful and magical places.

10 July

Wow, @egu.eu really badly wants candidates for treasurer and ECR union rep. To their credit I normally skim-read these emails but after the 30th identical email I did read it properly.

theconversation.comClimate change has already made Australians in one state much poorer, and more’s to comeIt’s time to recognise climate change for what it is. A new study shows it’s a current and ongoing threat to our standard of living.

10 June

How much is climate change already costing us? New work by Timothy Neal and Ben Newell shows that in New South Wales, Australia, that number is on average about $20k in lost income per person per year. Climate change is already a quality-of-life issue. theconversation.com/climate-chan...

nature.comCompound weather and climate events in 2025Nature Reviews Earth & Environment - Compound weather and climate events in 2025

9 June

Interesting example of a compounding event - March 2025 in Türkiye was so warm that fruit trees flowered early. Then hailstorms and cold temperatures came in April. Fruit crops were ruined and prices doubled for months. From this paper by @regclimo.bsky.social et al: www.nature.com/articles/s43...

rdcu.beCompound weather and climate events in 2025Nature Reviews Earth & Environment - Compound weather and climate events in 2025

9 June

This is an excellent recap of compound weather and climate events in 2025. It is also a great explainer of the different types of compounding that can occur, with strong examples. www.nature.com/articles/s43...

nature.comnature.com

Colin Raymond@regclimo.bsky.social

Which compound weather and climate events mattered most in 2025? In a new report in @natrevearthenviron.nature.com we've taken a systematic global view to survey these events and their impacts across 5 typologies. rdcu.be/fmeAh We hope it proves useful for looking back on 'the year that was'...

Tim Raupach reposted

ARC 21st Century Weather

@21stcenturyweather.bsky.social

4 June

New research led by Tim Raupach and Steven Sherwood and published in Nature Climate Change suggests the atmospheric conditions that favour hail formation are shifting towards cooler regions and cooler times of the year. For more: 21centuryweather.org.au/hail-conditi...

21centuryweather.org.auClimate change shifting hail risk towards winter cropsHail conditions on the move as winter crops face rising risk New research led by UNSW suggests that as the climate warms, the conditions that produce hailstorms are drifting towards the poles, leaving...

Tim Raupach reposted

UNSW Climate Change Research Centre

@ccrc.bsky.social

4 June

Where will hail risk increase in a warmer world? A new Nature Climate Change study by CCRC & ICRR researchers finds hail-prone conditions are shifting poleward, with winter hail risk projected to increase in some agricultural regions.

nature.comShifting hail hazard under global warming and effects on crop hail risk - Nature Climate ChangeHow hailstorms change with warming is not well understood. Here the authors use global projections with different hail proxies to show that hail-prone conditions shift polewards under warming, also sh...

3 June

In our new paper in Nature Climate Change, we show that hail conditions are projected to shift poleward with climate change, and that summer decreases and winter increases in hail hazard mean that winter crops may face rising risks from hail. www.nature.com/articles/s41...

theconversation.comClimate change may shift hailstorms towards Earth’s poles – new studyCosts from severe storms are increasing – and this global shift in hailstorm spells bad news for crops, too.

3 June

For an explainer and more context, see this article at @theconversation.com theconversation.com/climate-chan...

3 June

Coauthors on the paper are Raphael Portmann, @christiansiderius.bsky.social, and Steven Sherwood.

29 May

It's a good day when there's a new @boardsofcanada.bsky.social album out.

rdcu.beRising global hail damage potential in a warming worldNature - Hailstone trajectory simulations conducted under historical and future scenarios show a shift towards larger hailstones, resulting in global hailstorm-induced damage potential increasing...

28 May

Important new hail work by Zhang et al., in @nature.com today. Under warming scenarios globally, large hailstones become more frequent and smaller hailstones decline (with regional variation). Another reminder that reducing greenhouse gas emissions is imperative for a safer future. rdcu.be/fk8Fd

5 May

Our poster session for #EGU26 ITS4.4 is very active with lots of great discussion - interdisciplinary science from flooding rain, hail, to heat stress and financial risk.