Catawba rhododendron bushes can reach a height of 6'-8' with a spread of 4'-6'. Displays are most effective when rhododendron bushes are massed together. These are poisonous plants -- do not allow children to ingest any of the azaleas or rhododendrons.
Best Answer: Tornadoes are caused by winds. When a tornado forms the wind pressure around the tornado drops and that's what you see on the barometer, the pressure goes down.
Some variations (waves) may be seen. A rapid fall of air pressure is a sign for an approaching low and is a sign for bad weather. depending upon the drop-rate (per hour) you may exspect strong winds up to a gale. The dependeny pressure-drop-per-hour > wind is depending upon the latitude. In subtropic regions it is more difficult to predict the windspeed.