 EPOD - a service of USRA

The Earth Science Picture of the Day (EPOD) highlights the diverse processes
and phenomena which shape our planet and our lives. EPOD will collect and
archive photos, imagery, graphics, and artwork with short explanatory
captions and links exemplifying features within the Earth system. The
community is invited to contribute digital imagery, short captions and
relevant links.


 Knik Arm Tides of Alaska

   November 18, 2021

    High-low-tide_epod

   Photographer:  Gabrielle Tepp

   Summary Author:  Gabrielle Tepp

    Oceans are well known to have twice daily  tides, but not all
   tides are equal. Among many factors, the shape of  bays,
    topology of the sea floor, and  phase of the moon all affect the
   size of tides.  Cook Inlet, particularly  Turnagain Arm, has the
   third largest tidal range in North America and the largest in the
   United States. These photos show the difference in tides in the
    Knik Arm of Cook Inlet, along the coast of Anchorage, Alaska, where
   the average tidal range is about 26 ft (8 m). The top photo was taken
   on August 21, 2021 near the peak time of a 30 ft (9.2 m) high tide. In
   contrast, the bottom photo was taken three days later near a low tide
   of -1.5 ft (-0.5 m). The difference is quite dramatic! While hard to
   tell from the photos, the  gully is deep enough for a person to fit
   in. Fish Creek is located to the right of the imaged area and typically
   flows into the gully with a small waterfall. The highest tides,
   however, fill the gully to the same level as the creek. When the tide
   is low,  mudflats made of glacial silt are revealed.  Shorebirds
   like to feed in the small pools of water that form on the mud. Be
   careful if you decide to wander out though – it’s easy to get stuck in
   the mud and you don’t want to be stranded out there when the tide comes
   in!
     * Anchorage, Alaska Coordinates: 61.437, -149.770

Related EPODs

    Knik Arm Tides of Alaska  The Law of the (Colorado) River
    Utah’s Great Salt Lake  Archive - Orange Mound Spring  Soap
   Lake, Washington  Archive - Iguazu Falls
    More...

Hydrology Links

     *  Current Sea Surface Temperature
     *  NOAA Ocean Explorer Gallery
     *  Ocean Color
     *  What is hydrology?
     *  Tides and Currents
     *  Water Resources of the United States
     *  World Waterfall Database
     *  The USGS Water Science School
     *  World Water Database
     *  The World’s Water
     *  USGS Surface Water Information Pages

-
   Earth Science Picture of the Day is a service of the  Universities
   Space Research Association.

https://epod.usra.edu
 
