El Viento Zonda (the Zonda Wind) is a wind that is unusual in the world but that exists at the very least in Mendoza and apparently in Germany. Fast and strong wind comes from ocean side- in Mendoza’s case, the northwest, and drops the humidity levels drastically while also kicking up a lot of freshly dehydrated dirt and heating up the corresponding area quickly. Though Mendoza is a desert, humidity levels hover around 40-50% regularly. When the Zonda comes, it drops the humidity levels down to 1-2% humidity. That, in addition to the quick change in temperature and strong wind, results in extreme stress for the grape clusters in bloom or sometimes, even not in bloom.
The Zonda wind can damage a crop almost as much as a hail storm, depending on its timing during the life cycle of the vine. These winds tend to happen in the Mendoza area between August and November generally. This year, there was a strong Zonda wind for about 2-3 hours in late October, resulting in a lot of dropped blossoms and a lower tonnage year for the valley. It also bodes badly for the many paragliders who kick off from the Andes here, but luckily there are enough warning signs that people stop kicking off in time.
Like hail, the Zonda does more or less damage depending on its location and timing, but there tends to be a Zonda wind at least annually here.