By Pierre Ratte
Fire season is over. Risk signs with fire meter arrows read “Low” as of last week. This week, we’re bracing for wind, waves, rain and snow at elevation. Meteorologists predict a “bomb cyclone” as this goes to press, with four days of continuous rain. Not 40 days, though events suggest a “why” might be added—pun intended.
Torrential rain, rising tides and flood waters are not new, but names used to describe them seem to be. Recently, we’ve experienced “atmospheric rivers.” Now a “bomb cyclone” appears in almost every news report for this storm. Catchy phrases catch on and they catch one’s attention, an advantage in news reporting.
This column was started during the pandemic as a respite from news and today’s photo of a calm sea, sunset and seagull gliding by is a reminder that as the world turns, so do the tides and so does the weather, and it won’t be long before calm skies and seas return for us to meditate and wonder upon.
Fun Facts: There are two high and low tides per day. Since the Earth revolves one time per day, the pull of the moon’s gravity on water closest to it explains one high tide. The second and lesser high tide is indirectly caused by the moon when the centrifugal force of the Earth’s rotation ‘pushes’ water away when the moon is furthest away.
High tides split the lunar day and are approximately 12 hours and 25 minutes apart, hence “tide tables” predicting high and low tides moving about 25 minutes from one day to the next.
To be fair, bomb cyclones are a long-established term in meteorology, though it is only within the last few years that the term gained popularity. A bomb cyclone is defined by a storm’s pressure center dropping 24 millibars in 24 hours. This week’s storm is predicted to drop 50-60 millibars in 24 hours, from 1010 (approximately normal) to 960 millibars, a relatively rare and significant storm event.
Lower pressures denote more severe storms, and faster drops indicate rapid strengthening. 1 millibar = 100 pascal = 0.0145 PSI, all measures of pressure.
