ערפל כבד על תל אביב
Heavy fog in Tel Aviv
Photo: Yossi Navi
Heavy fog in Tel Aviv

Why is Israel blanketed in fog?

Expert says the unseasonal phenomenon that swallowed up buildings and reduced visibility is called radiation fog, and is triggered by several factors that can currently be seen across the center and south of the country

Ilana Curiel |
Published: 01.06.21 , 12:15
Heavy fog again descended on Israel on Wednesday, obscuring vision almost completely and swallowing up whole buildings across the country.
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  • So why is this unusual phenomenon happening? Prof. Hadas Saaroni of Tel Aviv University's Department of Geography and the Human Environment, explains.
    3 צפייה בגלריה
    ערפל כבד על תל אביב
    ערפל כבד על תל אביב
    Heavy fog in Tel Aviv
    (Photo: Yossi Navi)
    The fog that has blanketed the country in past days is known as radiation fog and is triggered by the unseasonable weather Israel has been experiencing.
    "There are various types of fog. In Israel we mainly see two: radiation fog, which is what we have been seeing in the past few days, and upslope fog, which occurs at high elevations during stormy weather," Saaroni says.
    Fog occurs when a cloud descends to ground level. If visibility is less than a kilometer, it is defined as fog. If visibility is between one to five kilometers, then it is called haze.
    "Radiation fog occurs when weather conditions are somewhat stable, usually when the ground is cold, as it is on long winter nights, and the wind is low," she says.
    3 צפייה בגלריה
    ערפל כבד בספארי רמת גן
    ערפל כבד בספארי רמת גן
    Heavy fog at Ramat Gan Safari Park
    (Photo: Ramat Gan Safari Park)
    "What occurs first is called an inversion, when the ground is colder than the air, which is the opposite of what happens as you get higher in elevation. Once the ground is cold, water vapor cannot evaporate into the air and it stays trapped on the ground level, turning into clouds and into fog."
    Saaroni says that the lack of rainfall has also helped create the fog, noting that this weather phenomenon is usually shorter, less consistent and more prominent during the spring, adding to its current exceptionalism.
    According to Saaroni, the fog is mainly being seen in central Israel and the northern Negev Desert because the strong winds in the north prevent the heavy fog from forming. Air pollution
    3 צפייה בגלריה
    טיסות נדחות בנתב"ג בשל הערפל הכבד
    טיסות נדחות בנתב"ג בשל הערפל הכבד
    Planes grounded at Ben-Gurion Airport due to heavy fog
    Air pollution is another contributing factor to the heavy fog in the Tel Aviv area, Saaroni says.
    "The more polluted air is helping to trap water drops and intensify the fog," she says. But even when it comes to urban areas, she says that this heavy fog is unusual.
    "Usually, cities form 'heat islands', with temperatures higher than the surrounding area, which can actually diminish the formation of fog, but the formation of fog is a very delicate game," she says.
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