Fog as an Abiotic Factor at Race Rocks

Wikipedia lists 9 different types of fog. Race Rocks experiences precipitation fog in the winter and steam fog in the summer. Steam fog occurs when cold air passes over warmer water.

Precipitation fog occurs when clouds of water vapor begin to condense. When the temperature reaches the dew point, vapor condenses to leaves behind small droplets of water. Fog is therefore a source of moisture. See example below: Many animals and plants can survive on the moisture left behind by fog. In tropical areas fog has the greatest effect on the surrounding ecosystem, providing water crucial to the survival of many plants and animals. Fog data for Race Rocks has not been collected , but the precipitation from either steam or precipitation fog is often recorded as a 0.2mm entry on the weekly rain record . An example is shown below.

Frequently in the summer, the Strait of Juan de Fuca is blanketed with fog. In this picture, the Olympic Mountains protrude above the fog bank which lies to the south of Race Rocks. (Photo taken June 17, 2006 on the remote camera 5 by PB)

 

The opening scenes of this video show how dense the fog was on one trip in June to Race Rocks. The boat was guided by radar.


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Click here to see our file on the Fog Horn at Race Rocks.
An early morning sunrise through the fog.
At 10:00 AM on July4 2007, this heavy fog enveloped the island. The sun was totally obscured, even though it was a hot sunny day back in Pedder Bay. A ” fog arch” could be seen to the west. This is caused by diffraction of light by the water droplets. It continued down into the ocean. (Photo from camera 5 remote by Garry F)

See the posts in this log noting the days with fog

SOME INFORMATION ON THE EFFECTS OF FOG ON ORGANISMS

In some coastal areas, tree species receiving the highest amount of pollutants via fog are experiencing damage. At Race Rocks, in foggy weather, the dried grasses will condense moisture from the atmosphere. This moisture allows the plants to recover from summer drought.On hot summer days the temperature at Race Rocks can be as high as 10 degrees C lower due to the fog compared to the adjacent shoreline of southern Vancouver Island.

Below is an example of “the perfect storm” –conditions for the creation of “Precipitation Fog”This particular week in September of 2006 has been chosen to show how we can get “rain” recorded in the tipping bucket sensor at Race Rocks even when there is “no rain in sight” at Race Rocks.. Late Monday evening of Sept 4, 0.2 mm. of precipitation was recorded. I recall seeing a heavy dew on the fields in Metchosin on that particular morning. At the same time, the dew point was 12.8. The humidity was 100%

 

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The temperature was at 12.8 degrees C, so the formation of moisture would happen on surfaces on the island. Previously, the light keeper would record this as trace when doing the rain calculation.

 

Students at Race Rocks on a foggy day

Find the light tower

Recent Posts

Wildlife Census

Woa, last week on Race Rocks. 3 months has FLOWN by, marked with very few intense winter storms and no resident Elephant Seals over the breeding season. We had a big female come ashore and do a bunch of feeding over the last month, and then a new (smaller) seal showed up on March 31st. She looks like a survivor of ‘scabby moult’ and she’s tagged! It’s a green tag (L334) meaning she was tagged in Año Nuevo, and probably 3-4 years old. We were so excited to have more than 1 Elephant Seal around we were very suprised to wake up this monring to another small Elephant Seal female! Could this be the begining of the moutling season for Race Rocks? Stay tuned to find out!

We figured if it’s the end of our time here, better try and leave the place better off than we found it. We installed Greg’s new electric fence concept on the jetty, and re-habed the N fence perimeter. Cleaned up a bunch of the scrap materials from previous infrastructure projects, and put the ladders away. We’re very fancy like that.

The Canada Geese have begun the laying season, which means a marked increase in their aggression as they start to defend their nests. It’s a battle between the Geese and the gulls (who are also getting ready to start laying), and we often wake up to a freshly cracked egg on the main walkway.

Mammals:

  • Stellar Sea lions: 12
  • California Sea lion: 14
  • Harbour Seal: 30
  • Northern Elephant Seal: 3

Birds

  • Gulls: 122
  • Cormorants: 68
  • Eagle: 8 Adult, 6 Juvenile
  • Turnstones: 20
  • Canada Geese: 7 – 3 breeding pairs
  • Oystercatcher: 18

It has been a LOVELY time on Race Rocks, and we’re always so grateful to get to spend time here. It’s such a beautiful spot with so much history, and it has Elephant Seals some of the time! We look forward to seeing a new Beachmaster take charge of the island, and for the opportunity to return.

 

Tristan & Courtney

Elephant Seals LOVE the smell of sawdust.

 

 

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