Naturalists’ World
Last Week in Nature
Record rainfall in the Pacific Northwest of North America and calm, dry deserts in the Arabian Peninsula, reveal how seasonal forces shape ecosystems in radically different ways across the globe.
Global Snapshot
Weather & Climate
A powerful atmospheric river stalled over the Pacific Northwest, delivering intense rainfall, flooding rivers, saturating soils, and triggering landslides.
Stable high pressure dominated the Arabian Peninsula, producing clear skies, dry air, and cooler desert nights.
An Arctic air surge dipped into parts of North America, sharpening the seasonal transition toward winter.
Geologic & Earth Systems
Several moderate earthquakes occurred along Pacific plate boundaries.
No major volcanic eruptions this week.
Fire activity remained relatively low globally.
Planetary Phenology
Northern Hemisphere:
Ecosystems leaning into winter
Migrations accelerating
Dormancy spreading across forests and grasslands
Cool-season activity increasing in deserts
Southern Hemisphere:
Moving toward peak summer
Longer days and rising biological activity
Breeding underway for many species
Coastal and marine productivity increasing
Global iNaturalist* Report
>450,000 Observations
>54,000 Species Observed
>61,000 Observers
>12,000 Observers
Global iNaturalist Project Spotlights
Two iNaturalist projects stood out this week for strong participation:
Panama Biodiversity 2025 - Santa María Belén: The Santa María de Belén Institute joins PanamáBiodiversa 2025 to document the biodiversity of Panama
Takayna BioBlitz 2025: This 11th annual BioBlitz continues to explore and document the biological diversity of the threatened ecosystems of north-western Tasmania.
Global iNaturalist Photo Highlights**
Anna's Hummingbird - Calypte anna - San Francisco, CA, USA
Fungus-growing ants (tribe Attini) - Acanthognathus brevicornis - Santa Catarina, Brazil
Emerald Jumping Spider - Paraphidippus aurantius - Teotihuacán, Mexico
Region 1: Western USA
This was a week of water. A warm, moisture-rich atmospheric river parked over Washington and British Columbia, dumping inches of rain in a matter of hours. With forest floors saturated the rivers rose fast. Some towns saw floodwaters pushing past roads and into neighborhoods. This close to winter, warm storms like this reshape everything from soil stability to salmon habitat.
Wildlife & Ecology
Salmon navigating high, turbid rivers
Waterfowl shifting into newly flooded lowlands
Elk and deer moving downslope
Fungi, mosses, and lichens exploding with growth
iNaturalist Snapshot:
>22,000 Observations
>2,900 Species Observed
>4,000 Observers
>2,000 Identifiers
iNaturalist’s users have contributed some great shots:
California Mantis- Stagmomantis californica - Carlsbad, CA, USA
Old-Growth Clam Lichen Xylopsora friesii - Pierce County, WA, USA
Yellow-billed Loon - Gavia adamsii - San Francisco, CA, USA
Region 2: Arabian Peninsula
Arabia sat under crystal clear skies the long, dry season settling into place. This is the desert’s quiet season, but not its dead season. Cooler nights mean more movement, more survival, more opportunity.
Wildlife & Ecology:
Migratory birds from Siberia and Europe arriving for winter
Desert foxes, sand cats, and jerboas becoming more active with cooler nights
Acacia and desert shrubs holding moisture deep underground
Raptors like kestrels and eagles patrolling open basins
iNaturalist Snapshot:
>400 Observations
>200 Species Observed
>80 Observers
>150 Identifiers
iNaturalist’s users have contributed some great shots:
Middle Eastern Short-fingered Gecko - Stenodactylus doriae - Sharjah Desert Park, United Arab Emirates
Euphrates Jerboa - Scarturus euphraticus - Al Hudud ash Shamaliyah, Saudi Arabia
Desert Hedgehog - Paraechinus aethiopicus - Al Hudud ash Shamaliyah, Saudi Arab
One Planet, Many Rhythms
This week showed how differently the Earth can behave, even at the same moment in time.
In the Pacific Northwest, water reshaped forests, rivers, and wildlife as powerful storms pushed ecosystems deeper into winter. In the Arabian Peninsula, silence and clarity defined the landscape, as cooler desert nights quietly reactivated life adapted to scarcity.
Flooded forests. Silent deserts. Two regions responding to the same seasonal clock in completely different ways.
Next week, the planet reaches a turning point.
The Winter Solstice arrives — the longest night in the Northern Hemisphere and the longest day in the Southern, and we’ll follow that moment to Earth’s extremes.
We’re heading to Greenland and Antarctica.
Arctic darkness versus Antarctic daylight.
Deep winter versus peak summer.
Locked sea ice versus active coastal ecosystems.
Two poles. Opposite seasons. One planet, changing in real time.
See you next week.
— Naturalists’ World
*This content uses publicly available data from iNaturalist. iNaturalist does not endorse or sponsor this newsletter.
**Thank you to everyone who shared open-licensed photos this week. Your generosity fuels education, research, and discovery across the entire naturalist community.