1 For automobiles a taxpayer uses for business purposes, the portion of the business standard mileage rate treated as depreciation is 23 cents per mile for 2013, the same as in 2012. 2  The IRS also publishes a standard mileage rate for the use of a vehicle for medical or moving purposes.
What causes continuous rolling thunder when no lightning visible? Thunder is caused by the rapid expansion of super-heated air as electrical spark passes through. What causes the long (ie some several seconds) of rumbling when no lightning is visible even at night during tropical downpours?
Every thunderstorm produces lightning, which kills more people than tornadoes each year. Thunderstorms also cause heavy rain, flash flooding, hail, strong winds and tornadoes. When warm and cold air masses meet, a thunderstorm can grow. In this activity, you will learn about convection and how air moves.