Big changes are still on track to come through the region over the next several days. A cold front approaches the coast Friday, kicking up some very strong winds under dry conditions, and a Red Flag Fire Warning has been posted for western Nevada for Friday afternoon, with valley winds that could gust to over 40 mpg. On Saturday, skies remain mostly clear as temperatures fall to near 70 degrees. By Sunday, highs drop another 10 degrees and we have a chance of valley rain and mountain snow, and travel over the passes could be affected. Valley temperatures bottom out Monday in the 50s with numerous freezing temperatures expected outside of the middle of town.
Back to wind blowing over plumbing vent pipes: On a calm day, the pressure in these pipes is essentially the same as what is outside. But if you blow a strong wind over the opening of the vent pipe, then Bernoulli’s principle comes into play. Technically speaking, Bernoulli’s principal states that as the speed of a moving fluid increases, the pressure within that fluid decreases. The upshot is if you blow air across the top of the vent pipe, you drop the pressure in the drain pipes, and that tries to suck the water down out of your toilet basin.