DATA COLLECTION
IBHS completed its first hail field study
in 2012. The findings from that research
led to creation of the first-ever, full-scale
indoor hailstorm in February 2013 at the
IBHS Research Center. This year, the research team collected nearly three times
as many hailstones as it did in 2012, including the largest hailstone recorded in
the two-year project history, which measured 4.21 inches in diameter.
While finding large hailstones was important, it is the amount of data collected on
smaller hailstones that could help uncover the answers to many unknowns.
“Bigger hailstones have a bigger mass,
and will cause damage at impact because of that higher mass,” Brown says.
“However, it’s when we get into the inch
and inch-and-a-half diameter hail that we
don’t know how the combination of hardness, size, and mass affect the amount
of damage – and most storms produce
hailstones that size, rather than the huge
stones. The more we know about this
kind of hail, the more accurately we can
understand how buildings are damaged,
and what can be done to prevent or reduce that damage.”
IBHS research teams also observed and
cataloged the types of hailstones commonly referred to as “slushy,” which will
provide valuable data for recreating similar hailstones. This could help answer
long-standing questions about the particular impact of this type of hailstone.
“A slushy hailstone probably wouldn’t
cause significant damage, but what kind
of impact does this kind of hail have on
an aged roof? We just don’t know yet,”
says Giammanco. “Data on this type of
hailstone are just as valuable as the hard
hail data. Knowing the type of hailstones
that are typically associated with a certain
kind of storm and its environment will allow insurers to more accurately address
claims.”
In May, three staff members from State
Farm joined IBHS researchers in the field,
which made it possible to deploy two
teams instead of one. “Having the extra
manpower enabled us to collect and measure twice as many hailstones, and facilitated getting the broad spatial coverage
that we did,” said Brown.
State Farm™ has a long history of hail re
search, said Rose Grant, State Farm pro
gram director. She called the IBHS re
search “critically important” and “really
impressive,” adding that “the information
gathered by the IBHS-led teams is data
that no one has previously collected; it is
providing new facts and details for us to
consider.”
DUAL-POLARIZATION
RADAR
The large collection of data during this
field study will help create a more accurate picture of how hailstones vary by
storm. These data will have significant and
immediate impacts on the effectiveness
of the National Weather Service’s (NWS)
network of dual-polarization Doppler radars, says Brown.
Although dual-polarization can greatly
improve estimates of hail size and location, the mathematical formulas used to
extract this information are still not perfect. Using data collected during IBHS’
field studies, the improved dual-polarization radar algorithms can narrow the
range of uncertainty, which will greatly
improve the weather forecast enterprise
and event classification, and risk analyses
conducted by the insurance industry.
“The dual-pol radar can detect hail and
what size it is, but that is something that
you have to train the analysis computer to
F