The inadvertent cloud-seeding effect occurs up to about 6 percent of the time at major airports.

Prior to massive flooding early in 2011, long-term drought plagued the Australian state of Queensland . As part of a broad research program on cloud seeding, NCAR researchers have been steadily crunching data from a 2008–09 field project that looked into how to make the clouds drop more rain on the region.

A new study led by NCAR’s Wei Yu and CU-Boulder’s Weiqing Han looks at the effects of the Madden-Julian Oscillation (MJO), the largest source of intraseasonal (within one season) variability in the tropics, causing wet and dry periods to alternate.

The surfeit of snowfalls across the U.S. East Coast over the last two winters brought ample evidence of just how much the white stuff can vary from place to place—and how difficult it is to assess accurately.