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

August 24

Much quieter day workwise today.

The sea lions are taking over! They have knocked the fencing down in several places and once again have cleared the fence posts from the jetty. I am conceding defeat! I know Greg and Richard are planning to redo the fence system this week, so the sea lions can claim victory–for now.

During yesterday’s census, I saw a Glaucous-winged Gull with a seriously broken wing. It looked like an old injury given the condition of the wing. I couldn’t relocate it after viewing it from the tower, but today it was near the solar panels. I managed to catch it and will take it to WildARC when I leave on Monday.

The bird of the day remains unidentified. I flushed a small sparrow twice today, but it went too far for me to get a positive identification. I suspect it is a Savannah Sparrow. I am annoyed I didn’t get a better look as there are very few songbirds here.

The entangled sea lion is still present. Fingers crossed for a rescue soon.

Facility work:

  • Clean the solar panels
  • Clean the west and north windows of the Science Building
  • Took hydrometer readings of the batteries in the generator building.

Weather:

  • Sky: clear and sunny all day
  • Wind: variable 0 – 20 knots
  • Sea: rippled
  • Air temperature: low 13 °C, high 27 °C
  • Seawater temperature at max flood: 10.9 °C

Photos from today:

Western Gull, an uncommon species for Race Rocks, although there are a few who are breeding with Glaucous-winged Gulls on site.

One of five Ruddy Turnstones seen today

 

 

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