July 21, 2017
Summer Wave,
vol.
5,
no.
5,
Water Resources Research Center,
Tucson, AZ,
July 21, 2017
On July 11, the record-breaking string of 100-degree-plus temperatures that had baked Southern Arizona in June was broken by the arrival of glorious, quenching monsoon rainfall. The monsoon season officially begins on June 15, but most Tucsonans don't truly believe that the annual monsoon has arrived until the raindrops fall. On average, Arizona receives about half of its annual rainfall during the monsoon season of June 15 to September 30.
In addition to replenishing basin groundwater, the monsoon season recharges riparian areas like the Upper San Pedro River Basin. Dry washes or rivers like the Rillito and Santa Cruz can become filled with raging waters due to water downpour and flash floods. The downpour from monsoon thunderstorms spurs plant growth, including wildflowers, shrubs, and other plants that provide food for migrating birds. Hummingbirds gather in numbers. Wildlife appears in abundance, including the toxin-producing Colorado River Toads, as well as bats and butterflies. All life in Arizona seems to be stirred with the onset of our yearly rains.