# 🌫️ FOG _“The fog comes on little cat feet. It sits looking over harbor and city on silent haunches and then moves on.”_ Carl Sandburg Fog forms when air temperature meets the dew point, dropping visibility below ⅝ statute miles. The dew point is the temperature at which air must be cooled for it to become saturated with water vapor, leading to condensation Condensation is a change in the state of water from a gaseous or vapor form into liquid form Water consists of molecules — in vapor form the molecules are energetic as in faster moving and farther apart —cooler air temperatures slows the molecules and so they become closer together — when they reach a low energy point vapor becomes liquid — Condensation can be viewed as the opposite of evaporation; while condensation results in droplets of water forming on some surface, evaporation is a change of state where water goes from liquid water to water vapor. ## Types of Fog The six major types of fog—categorized by how they form -- what cools the air or adds moisture | Fog type | How it forms | Where you see it | | ----------- | ----------------------------------------------- | ---------------------------------------------- | | Radiation | Clear, calm nights as the ground cools | Valleys, low areas, inland regions | | Advection | Warm damp air over cold surfaces | Coasts, the Grand Banks, San Francisco summers | | Evaporation | Cool air over warm water, or rain thru cool air | Lakes at dawn, after summer storms | | Upslope | Damp air pushed up a mountain slope | Rockies, Appalachians, Pacific Coast Range | | Freezing | Supercooled droplets freezing on contact | Mountain tops, polar regions, deep winter | | Hail | Air chilled by melting hailstones | Rare; right after a hailstorm in light wind | - **Radiation fog:** Forms on clear, calm nights. Stays put. - **Advection fog:** Warm damp air over cold ground. Drifts. - **Evaporation fog:** Cool air over warm water, or rain through cold air. - **Upslope fog:** Damp wind pushed up a slope until it condenses. - **Freezing fog:** Supercooled droplets that freeze on contact. - **Hail fog:** Rare patchy fog right after a heavy hailstorm. Valley fog: Valley fog is a special type of radiation fog. It forms when air along ridges and high slopes cools and flows into the valleys below. ## Fog vs Mist Mist and fog are two common types of atmospheric conditions characterised by the condensation of water vapour into tiny droplets within the air near the Earth's surface. Fog is denser than mist and reduces visibility to less than 1,000 meters, while mist allows for visibility greater than 1,000 meters. Fog typically lasts longer and can cause more significant disruptions than mist Q: What's the difference between fog and mist? A: If you hit it its fog, if you don't it's mist. ## Humboldt Fog Humboldt County, California, typically experiences advection fog, which forms when warm, moist air moves over cooler surfaces, such as the cold ocean waters along the coast. This type of fog is common in coastal regions, especially during the summer months. Advection fog is a significant aspect of Humboldt County's coastal climate, contributing to its unique weather patterns and ecosystem. Coastal marine fog is an important meteorological phenomenon for California.  Fog season in Humboldt primarily runs from late May through September. - **Summer (June through August):** Often referred to as "June Gloom," this is the peak of heavy coastal fog. It regularly rolls in overnight and in the mornings, frequently burning off in the early afternoon.  - **Autumn (September and October):** Generally the clearest and warmest time of the year on the coast. - **Winter and Spring (November through May):** While you may occasionally experience radiation fog, this is typically the rainy season, characterized by overcast skies and high fog in the forested mountains. ## Fisting Fisting = Fog + Mist Fog and mist can occur simultaneously, but they are distinct phenomena. ## Fog Facts The Grand Banks of Newfoundland are often considered one of the foggiest places in the world. In United States, Cape Disappointment, Washington, averages about 2,552 hours of fog per year, more than any other U.S. weather station. The foggiest places in the world are often areas above cold ocean currents. Most sea fogs are types of advection fog. Steam from a hot shower in a cold bathroom is technically a type of evaporation fog. For meteorologists, the ability to forecast fog can be very tricky. Fog forms when the moisture in the air reaches its dew point. It then condenses from water vapor into water droplets. Arcata–Eureka Airport (ACV) is considered to be the foggiest airport in the world. The weather in this part of Northern California is so unpredictable that the United States military has made it a base for its all-weather training. United States Navy constructed the airport during World War II to test its defogging systems. On average, the airport suffers from dense fog or rain for 97 days of the year. Dense fog tends to only occur during colder months of the year, but it is possible to have foggy days in the spring and the autumn. One thing to bear in mind is that fog can be very localized, which means where you live may be fine, but a few miles away, at the airport, it can be fogged in. Fog is most likely to build up when conditions are colder and the nights are longer. It is often the result of clear night skies and very little or no wind. Niebla (Sea fog lichens)? ## Fog is alive w/ bacteria Fog is alive - fog droplets can briefly host living bacteria that grow and help remove pollutants from the air, making fog a temporary aquatic habitat rather than a sterile mist [Growth and formaldehyde degradation of photoheterotrophic Methylobacterium within radiation fogs](https://journals.asm.org/doi/10.1128/mbio.00463-26?_bhlid=c76d26373d313b9efae3bec88abe3a8fc28db05a) This study focused on only radiation fog events — radiation fog and advection fogs are different — radiation fogs form locally in stagnant air masses and which is advantageous to detecting internal aerobiome dynamics — this might occur in other fog events like advection — just hasn’t been studied microbiologically ## Fogs are cloud A cloud—either stratus or stratocumulus—is called “fog” when it is low or touching the ground. Marine fog forms as a result of complex interactions between ocean evaporation, aerosols, atmospheric pressure, vertical air layering, onshore-offshore temperature gradients, and coastal mountain topography. ## Redwood fog drip Redwoods "Sequoia sempervirens" forests in California receive approximately 30–40% of their moisture from coastal fog by way of fog drip ## Fog Harvesting Fog collection aka fog harvesting is the harvesting of water from fog using large pieces of vertical mesh netting (aka fog fence, fog collector or fog net)to induce the fog-droplets to flow down towards a trough below. ## Misc *In nature, everything has a job. The job of the fog is to beautify further the existing beauties!"* - Mehmet Murat Ildan