Snell's window

A Snell's window is the optical phenomenon resulting from the refraction of light moving through an air-water interface compressing the above-water view from 180 to about 96 degrees when looking up while submerged such as when scuba diving.

Snell's window
Trout, ripples, and a Snell's window in an Alaskan stream.
Alaska Copper River Delta Snell's window South Central Alaska Spring United States biosphere in situ naturalworld underwater
Under a Snell's window
Chinook Salmon (Oncorhynchus tshawytscha) under a Snell's window
Actinopterygii Chinook Salmon Chordata Class Actinopterygii Infraclass Teleostei King Salmon Neopterygii Oncorhynchus tshawytscha Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Snell's window Subclass Neopterygii Summer Teleost Teleostei Vertebrate biosphere chordate in situ naturalworld nature underwater underwaterphoto wild
Foraging under a Snell's window
Coho Salmon (Oncorhynchus kisutch) parr and fry foraging under a Snell's window
Actinopterygii Chordata Class Actinopterygii Coho Salmon Infraclass Teleostei Neopterygii Oncorhynchus kisutch Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Silver Salmon Snell's window Spring Subclass Neopterygii Teleost Teleostei Vertebrate biosphere chordate fry in situ naturalworld nature smolt underwater underwaterphoto wild wild trout
Forested setting
A male Sockeye Salmon (Oncorhynchus nerka) holds a position high over a redd site as the female approaches from downstream in a forested setting as evidenced by the view through a Snell's window.
Actinopterygii Chordata Class Actinopterygii Infraclass Teleostei Neopterygii Oncorhynchus nerka Pacific salmon Phylum Chordata Red Salmon Salmonidae Salmoniformes Salmoninae Seacam underwater housing Snell's window Sockeye Salmon Subclass Neopterygii Teleost Teleostei Vertebrate biosphere chordate courtship in situ naturalworld nature spawning behavior spawning pair underwater underwaterphoto wild
Spawning migration of maturing Sockeye Salmon
Spawning migration of maturing Sockeye Salmon (Oncorhynchus nerka) under a Snell's window. A drifting Willow leaf is a sign of the coming winter.
Actinopterygii Alaska Chordata Class Actinopterygii Infraclass Teleostei Neopterygii Oncorhynchus nerka Pacific salmon Phylum Chordata Red Salmon Salmonidae Salmoniformes Salmoninae Seacam underwater housing Snell's window Sockeye Salmon South Central Alaska Subclass Neopterygii Teleost Teleostei United States Vertebrate biosphere chordate in situ naturalworld nature underwater underwaterphoto wild
Under a Snell's window
Under a Snell's window, a Pink Salmon (Oncorhynchus gorbuscha) guards her brood.
Actinopterygii Alaska Chordata Class Actinopterygii Humpback Salmon Infraclass Teleostei Neopterygii Oncorhynchus gorbuscha Pacific salmon Phylum Chordata Pink Salmon Salmonidae Salmoniformes Salmoninae Seacam underwater housing Snell's window South Central Alaska 2 Subclass Neopterygii Teleost Teleostei United States Vertebrate biosphere chordate in situ naturalworld nature underwater underwaterphoto wild
Eulachon (hooligan) spawning run
Winterscape in April visible through the Snell's window above a Eulachon (hooligan) spawning run in Alaganik Slough, Copper River, Alaska; Thaleichthys pacificus; Osmeridae
Actinopterygii Alaska Chordata Class Actinopterygii Copper River Delta Eulachon Infraclass Teleostei Neopterygii Osmeridae Osmeriformes Phylum Chordata Seacam underwater housing Snell's window South Central Alaska Spring Subclass Neopterygii Teleost Teleostei Thaleichthys pacificus United States Vertebrate biosphere chordate in situ marine life naturalworld nature underwater underwaterphoto wild