The Chemistry of Storms – Hobart and William Smith Colleges \
The HWS Update

The Chemistry of Storms

Snowden Jones '18 conducts research with weather balloons on the Quad.
Snowden Jones ’18 conducts research with weather balloons on the Quad.

After chasing storms across the United States as part of the “GEO 299 Geoscience Field Studies” course,  geoscience majors Snowden Jones ’18 and Aubrey Phillips ’18 returned to campus this summer to work with Assistant Professor of Geoscience David Finkelstein to study rain and snowstorms that have occurred in Geneva over the past five years.

Jones and Phillips combined their interests and hands-on classwork experiences in meteorology and geochemistry to test the idea that the path of a storm can impart unique chemical signatures. The students worked to answer a number of questions: Do all precipitation events have the same chemistry? Why do some storms have water with low pH while others are near neutral? Does the storm path affect the chemistry recorded in the precipitation (rain or snow)?

Previous summer research students had already analyzed the water from rain and snow events in 2014 and 2015. They found higher chloride values from the moisture sources of storms originating in the Gulf Coast and Atlantic Ocean, while moisture sources to the west had higher calcium. To ensure that those findings were not aberrations and to expand the analyses of storms through the summer of 2017, Jones and Phillips catalogued the samples and analyses from last summer’s research to create a database.

In addition, Jones collected samples from storms that raced through the area this summer and found that those with a high rate of rainfall had the lowest pH. In addition, he created a more rigorous approach to identifying a storm’s moisture source, calculated back trajectories (which trace the path of moving air in reverse, back to where it started) and archived radar data that is used to confirm the path of a storm.

“My summer was divided between collecting, organizing and analyzing water samples,” he says. One result of the group’s work was determining that storms which originated from the Great Lakes, had more neutral pH and unique chemical signatures because water vapor distilled from these lake waters were more alkaline than source waters associated with other storm paths.

“This may have implications for agriculture or for how local pond versus lake water chemistries could evolve if lake-effect storms become the dominant path,” says Finkelstein. “For example, if crops are compatible with alkaline to near neutral pH of rain, then there is no harm done, but if a crop requires a more acidic rain then lake-effect storms may be problematic.”