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

The Myth of the Oil Spill Clean-Up

The Myth of the Oil Spill Clean-Up: Why Our Winds Leave Us Defenseless Nearly Half the Year

By Shamseddin Alsesheikh and Garry Fletcher, with research assistance by Gemini AI

Given the new political push to increase tanker traffic past Race Rocks in may be appropriate to visit an inconvenient truth. 

As oil tankers carrying heavy crude transit the narrow corridor of the Strait of Juan de Fuca, coastal communities along southern Vancouver Island are routinely assured that a “world-class” marine spill response regime stands ready to protect our shores. With the Trans Mountain expansion elevating tanker traffic to as many as 34 vessels per month, these assurances form the foundation of public safety promises.

However, five years of meteorological data from Environment and Climate Change Canada’s weather station at Race Rocks reveal a major flaw in this safety net: the mechanical equipment meant to contain and skim spilled oil is rendered unusable nearly half the time.

Under Transport Canada’s TP 14909 Environmental Response Standards, standard mechanical recovery equipment—such as oil containment booms and floating skimmers—loses effectiveness when sustained winds reach 28 km/h (15 knots). Beyond this threshold, wind-driven waves shear oil underneath containment skirts, splash slicks over barriers, and create dangerous working conditions for small response vessels.

An analysis of hourly climate records from 2021 through 2025 demonstrates that wind speeds at Race Rocks reached or exceeded 28 km/h for 43.1% of all recorded hours across the five-year period.

Far from being an occasional winter storm issue, this operational blackout is actually most severe during the summer. Driven by intense thermal pressure gradients between the hot interior and the cool ocean, gap winds funneling through the Strait cause cleanup equipment to be inoperable for an astonishing 79.1% of all hours in July.

Annual Response Inoperability at Race Rocks (2021–2025)

(Source: Environment and Climate Change Canada, Race Rocks Station 10943, 2021–2025)

When mechanical containment fails, surface oil spreads rapidly with wind and tidal currents, threatening ecological reserves, migratory bird habitats, kelp forests, and endangered marine life like the Southern Resident killer whales.

If cleaning up an oil spill on the water is physically unfeasible 43% of the year—and nearly 80% of the time in mid-summer—policy makers cannot rely on post-spill skimming as a primary line of defense. Transport Canada and the Pacific Pilotage Authority must prioritize strict preventive measures. This includes establishing mandatory transit pauses for laden tankers during high-wind events and enforcing high-capacity tethered escort tug requirements along the entire transit corridor.

We cannot control the weather in the Strait of Juan de Fuca, but regulators can—and must—control when and how crude oil tankers navigate it.

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