Dr. Sam Anderson

a) – d) The fraction of heatwave days with more than 1 mm of precipitation, for winter (DJF), spring (MAM), summer (JJA), and autumn (SON; columns). e) – h) The fraction of non-heatwave days with more than 1 mm of precipitation. i) – l) The difference in the fraction of wet-days between heatwave and non-heatwave days. Blue indicates where heatwave days are more frequently wet than non-heatwave days, and red indicates where heatwave days are less frequently wet than non-heatwave days.

... and that there are strong seasonal patterns in precipitation characteristics, too. Check out the full paper for more details (and maps!).

A map of 14,425 basins across North America from HYSETS, coloured according to the clusters defined by the basins’ heatwave-precipitation frequency curves. Basin colours and their corresponding cluster are defined by the colourbar (right). An inset of the west coast (left), with the inset area shown by the bounding box in the full map. White areas are those without basins in the HYSETS database.

We find that there are strong spatial patterns in where precipitation happens during heatwaves...

Heatwaves can be dry, or wet, or dry-then-wet, or wet-then-dry, or wet-then-dry-then-wet, or...

It all depends where you are and what season it is! Our new paper dives into the cool world of heatwaves and precipitation.

doi.org/10.1088/3033... @ioppublishing.bsky.social @sfuscience.bsky.social

Climate shift index for June 23, 2025 across the eastern half of the United States. This is for minimum temperature and there is a level 5 change in likelihood due to climate change for most areas.

Today's Climate Shift Index (CSI) is highlighting just how much climate change has made today's heat wave more likely to occur, especially for the warm nighttime temperatures.

Follow along with real-time and forecast CSI global maps from @climatecentral.org at csi.climatecentral.org/climate-shif...

A map of the Northeast USA showing the forecast risk of unhealthy heat for Tuesday, June 24. High risk extends from NYC to Raleigh to Indiana.

I spend most of my time thinking and writing and researching about heat waves. Being in one reminds me why -- extreme heat cuts deep.

Not only did this event foreshadow the globally-unprecedented heatwave that engulfed Western North America 80 years later in 2021, but it is a stark reminder of the long scars carved by climate extremes.

A photo of myself and my research poster, titled "The Unprecedented Western North American Heatwave of 1941: Digitized Newspapers to Understand Far-Reaching Social and Physical Impacts".

✨ Archive newspapers teach us about the social and physical impacts of historical climate extremes ✨

Last week at @egu.eu I presented my recent work in which I use archived newspapers across North America in addition to climate reanalysis data to reconstruct "the lost heatwave" of 1941.

Screenshot of Vancouver byelection results showing Sean and Lucy each with more than 30,000 votes, way ahead of the rest.

Huge congratulations to @lucymaloney.bsky.social @onecityvan.bsky.social and @seanorr.bsky.social @copevancouver.bsky.social!

Vancouver’s two new City Councillors!! 🥳

do you or someone you know work at noaa and are dealing with the AWS contract debacle? i'd love to talk to you :) signal mollytaft.76, you can speak anonymously

Headline from The Globe and Mail in 1941: "Removal of Tariff Helps Manufacture"

And, from two days later...

Newspaper headline from The Globe and Mail in July 1941: "Farm betterment / Tariff ups living cost of farmers"

Headlines from The Globe and Mail in 1941 feel highly relevant in the modern day, too.

Who’s afraid of trans visibility? | Xtra Magazine OPINION: On International Transgender Day of Visibility, we must call out Canada’s right for weaponizing the triumph of our visibility

From #TDOV last year: "For the same reasons that trans people celebrate trans visibility .. so too do anti-trans actors fear it for awakening another person who questions or challenges the traditional heteronormative, sexist, racist version of capitalism we live in."
xtramagazine.com/power/identi...

On an island carved by climate extremes, I came to better understand our own polarization The fractures in our social and political fabrics are, in some ways, not unlike the landscape of Devon Island, in the High Arctic: torn open and deepened by extremity, unhidden and cascading

On cascading extremes in climate and politics, through my experiences in the Canadian High Arctic last summer. Check out my latest in The Globe and Mail here: www.theglobeandmail.com/gift/0cdc78b...

This is fascinating -- and those figures are incredible!

YouTube video by Sam Anderson DAYS ON DEVON ISLAND | Polar Film Festival 2025 | Cinematic 4K Arctic Drone Footage

I submitted this short film to the 2025 Polar Film Festival to express some of the experiences we had during our time on Devon Island this past summer. The Canadian High Arctic is evocative and remarkable, and I'm so grateful to have spent that time in Nunavut!

www.youtube.com/watch?v=PtoS...

A map of Canada, pointing out the location of Stag Island, the southernmost part of Nunavut. Stag Island is further south than Edmonton, AB, and nearly as far south as Calgary, AB.

Today I learned that the southernmost point of Nunavut -- Stag Island -- is deep in James Bay. This means that Nunavut extends further west than Alberta, further east than New Brunswick, near the North Pole, and further south than Edmonton.

The geography of this country is amazing. 🇨🇦

CANADA spelled out using Landsat images. Source: https://landsat.gsfc.nasa.gov/apps/YourNameInLandsat-main/

Canada standing strong 🍁🇨🇦

Super interesting, nice work!

After becoming increasingly enmeshed in the wildfire world, you start to notice things about the way we've systematically altered our relationship with the natural environment in a way that has increased the risk of destructive fires. And then you stop being able to unsee them.

A mountain river flows in the Canadian Rockies

An outflow of ice from the Illecillewaet Glacier, in Glacier National Park, British Columbia

A headline from an op-ed in The Globe and Mail: "Glacier's are Western Canada's best friends. We'll need them against climate change -- just as much as we'll need each other"

Hi! An introduction to my new followers:

1. I research how heatwaves impact rivers and water systems

2. I got into climate science because I love glaciers and snow, and I think it's nice when we have water to drink

3. I write about climate, water, and us

❄️🔥💧☀️

Hydrology Paper of the Day @sam-science.bsky.social on how extreme temperature events affect hydrology, streamflow, and glacier ablation in the context of climate change: British Columbia and Alberta, Canada; CNN-LSTM machine learning; and numerical experiments to explore processes and sensitivities

Maps of North America, showing how heatwave conditions are either wetter or drier than normal conditions. Results are shown in terms of both frequency of precipitation, and precipitation amount, for each season.

Heatwaves aren't always dry -- and it turns out that the precipitation characteristics of North American heatwaves vary strongly in space and time. Come learn more at the Global Environmental Change online poster session at AGU!

#climatechange #earthscience #heatwave #AGU24

#arcticscience #dronephotography #climatechange #fieldwork

YouTube video by Sam Anderson Devon Island: Us

Part 3: Us

www.youtube.com/watch?v=tPlN...

YouTube video by Sam Anderson Devon Island: Landscapes

Part 2: Landscapes

www.youtube.com/watch?v=5LhN...

YouTube video by Sam Anderson Devon Island: Water

From this summer's fieldwork on the remarkable Devon Island in the Canadian High Arctic: three short videos, on the theme of "Water, Landscapes, and Us".

Part 1: Water

www.youtube.com/watch?v=wVg7...

Opinion: Our federation helped make Alberta rich in water. Now, that dam is breaking Albertans seeking sovereignty forget that the province’s agricultural success is a gift of pan-governmental cooperation – something they can’t lose sight of, in the face of serious water shortages

Water management links local and federal interests. Federalism -- through finance, policy, and geography -- has long been key to reshaping the water landscape in Alberta. Here are some of my thoughts for The Globe and Mail at a moment of jurisdictional crossroads in the Prairies.

After 15 months, five different reviewers, and three rounds of review -- I am thrilled to have this out. And on a Friday!

What's really interesting is if mean temperatures are warmer, these responses change differently than the underlying streamflow -- with implications for how we think about heatwave-driven flooding in spring!

Glacial and nival rivers respond to heatwaves with an initial surplus, and a delayed deficit -- here we quantify how these responses vary as a function of heatwave timing and glacier coverage.