How High Are the Low Clouds?

Strange as it seems, all these clouds are the same height, that is, their bases all rest at the same altitude. These are cumulus clouds, one of the "low" clouds.

  For me, one of the most challenging aspects of studying the clouds is determining how high they are above the earth. Most meteorology books and cloud charts provide altitude levels for the ten basic cloud types. (Recall that altitude is the height of something above the earth, elevation is the height of something attached the earth--such as a mountain or office building).
   Cloud heights are given in feet or meters and describe the altitude of the base of the cloud, the base being synonymous with the bottom of the cloud. Let's look at a few examples of low clouds--clouds with their bases resting from ground level up to 6,500 feet (2000 meters). Low clouds include stratus, stratocumulus, cumulus, and cumulonimbus. I find this strange because this means low clouds include the ground-hugging fog (a type of stratus) as well as the towering cumulonimbus clouds, which often rise to the top of the troposphere at 39,000 feet (12,000 meters).
Here we have very low stratus clouds (the fog) skirting this foothill in the Cascade Mountains and  low stratocumulus clouds above them. 

The gray cloud is a type of cumulus cloud called cumulus fractus--a  remnant of  a larger cloud. These often form below other clouds, including the cumulonimbus in the background here. I couldn't capture the entire cumolonimbus here, but the telltale dark base and wispy-edged anvil-shaped wedge in the lower right corner of the photo are the give-away. That, and the fact that there were other cumulonimbus clouds in the area that day. And I got soaked by one of them.

Here (from my last posting) is a "low" cumulonimbus rising behind and from  its dark and stormy base where other low clouds--cumulus and stratocumulus cavort. (Photo courtesy M.D. Ruth)