Several months ago, I wrote about the amazing October rains we’d received (see “An October like no other”). The early moisture, combined with warmer-than-average temperatures, gave our annual grasses an early start. Since those October storms, we’ve continued to receive substantial moisture – more than 20 inches (over half of our average annual rainfall) since October 1! Since I started paying attention to the grass nearly 30 years ago, I can’t remember going into a new year with this much green forage.
And yet the National Drought Monitor still shows our part of California to be “abnormally dry.” I suppose that it’s an indicator of how severe the drought was for us in 2014 and 2015 – abnormally dry seems like a vast improvement! For me, our current drought status underscores the profound difference between droughts and other weather phenomena – you don’t know you’re in a drought until it’s well started, and you don’t know it’s over until after the fact.
Our foothill rangelands typically go through two dormant seasons – even in normal rainfall years. We think of these as grass “droughts.” Since our forage plants (grasses and broad-leaf forbs) are mostly annuals, the first of these dormant seasons is obvious. The classic golden-brown grasses of our California summers represent the annual warm season drought in our Mediterranean climate. This dry forage doesn’t have enough protein in it to support our sheep – which is why we either supplement their protein intake or move them to irrigated pasture.
The second dormant season is less obvious. At some point (usually in late November or early December) the shorter days and colder temperatures put our newly germinated green grasses into dormancy. With the sun at a lower angle in the sky, the soil doesn’t absorb as much heat – once the soil temperatures drop below 50 degrees F, grass growth comes to a halt. I checked the soil temperature reading for this morning at the California Irrigation Management Information System (CIMIS) weather station near Auburn – we’re at 45 degrees F. Our morning low temperatures at the ranch have been in the mid-20s. In other words, we’ve hit our winter grass “drought.” Our job now is to ration the grass that’s already grown this fall until the days get long and warm enough to get the grass growing again (usually in early March – just about the time our lambs start to arrive).
In the meantime, I hope the precipitation keeps coming! We’ve had enough rainfall that the seasonal creeks have started flowing and the stock ponds have started filling. Snow in the mountains will mean the rivers and irrigation canals will keep flowing next summer. To paraphrase my friend and fellow rancher Tim Koopmann (who raises cattle in the Bay Area), the spring rains make the year. Keep it coming!