The Documentation and Investigation of Pyrocumulonimbus Events

Pyrocumulonimbus clouds (pyroCb) are relatively dry thunderstorms produced by intense wildfires that transport smoke plumes into the upper troposphere. Often these plumes reach into the lower stratosphere, whereupon the smoke can be transported thousands of kilometers from the source region in a matter of days. The documentation of these pyroCb events has increased during the last few years with funding from the National Oceanic and Atmospheric Administration (NOAA) at the University of Wisconsin-Madison. These cases have been documented with near-real-time imagery from different geostationary and polar-orbiting satellites as well as ancillary data (http://pyrocb.ssec.wisc.edu). From these documented cases we investigate different meteorological conditions that may be conducive to a pyroCb event occurring. To better characterize an atmosphere that is more favorable for pryoCb generation, we examine the mid-level water vapor, upper-level divergence, and Haines Index (Peterson et al. 2014). In addition, convective available potential energy (CAPE) is investigated, but is determined to be ineffective for determining if a pyroCb event might occur. We will summarize the documentation of pyroCb events over the last few years, as well as show what meteorological conditions appear to be more conducive to pyroCb events forming.