By the time you read this—cumulonimbus gods willing—it will have begun raining at your house.
The day I sat down to start writing this, I could smell the faintest hint of monsoon moisture, but above my house, I saw only the same bitterly hot blue sky that had persisted for months. Despite a 60 percent chance of deliverance, that day became the 81st in a row without rain, one of the longest stretches of precipitation futility in Tucson's history.
Such is the mystery of the monsoon. If you pay any attention to these things, you know that blowing a 60 percent call is nothing—over the years, I've seen 90-percenters come up dry. The seasonal wind pattern that triggers our summer thunderstorms, known as the North American monsoon, is one of the most difficult climatic phenomena in the world to predict.
No surprise, then, that this year's pre-monsoon briefing presented ... a great big shrug. In technical terms, we have "equal chances of above-, below- or near-average rainfall for the monsoon season." But even this non-committal shot in the dark understates the potential variability. Among individual forecasters, one predicted a "dismal" season, while another foresaw an early onset and bountiful rain.
Part of the challenge lies in the sheer number of variables in play. The Climate Prediction Center, the author of the aforementioned shrug, uses 41 different analysis tools to zero in on something approaching an educated guess. It's not just wind, temperature and humidity; everything from the previous winter's precipitation to sea-surface temperatures to the amount of water plants are pushing out through their foliage hundreds of miles away plays a part. It's about as close as you can come to meteorological magic.
Some climatic consequences are not so hard to predict. Everybody and their second cousin knew it would be a bad fire year. Some forecasters went for "catastrophic" and "unprecedented," terms that proved all too accurate. As of this writing, the number of Arizona acres scorched this year is approaching 900,000, roughly five times the historical average. What matters even more is the severe intensity with which many of those acres have burned.
The dynamic is clear as the June sky: The world is warming. Temperatures are higher; snow pack melts earlier; droughts are more extreme; and winter moisture is scarce. Parts of Cochise County near the still-smoldering Chiricahua Mountains received virtually no precipitation last winter.
Humidity levels this spring were incredibly low. Of the first 10 days of May, seven set record lows for daily average dewpoint in Tucson. Relative humidity sank as low as 1 percent. Dry conditions were compounded by a freakish February cold snap that transformed vast swaths of living vegetation into crackling-dry kindling. Throw in the unusually strong and dramatically defined La Niña—which triggered record snowfall and flooding up north, vicious tornadoes back east, and nothing but dry, blasting winds here—and you have an unprecedented recipe for calamity.
I called staff scientist Zack Guido at CLIMAS (Climate Assessment for the Southwest) to pick his brain about the crazy aberrations I've been noticing. He immediately stressed that this fire season jibed perfectly with conclusions drawn from years of sound climate science and predictive models.
I asked him how the monsoon will be affected by ongoing climate disruption—in particular, the increasing tendency toward extremes. He called it the "holy grail" of climate research—examining the distribution and extremity of weather events—but then said the interrelationships will be even harder to figure than the monsoon itself. There are gaps in the data, and there is a long way to go to discern the fate of the monsoon in coming decades. Possibilities range from dangerously intensified chubascos the likes of which we've never seen, to the breakdown and disappearance of the monsoon altogether—a true climapocalypse.
One thing's for sure: We need to invest in climate research now, or resign ourselves to a world of unpleasant surprises. Sadly, Zack will be the first to tell you that the political climate is as treacherous as the weather. "It's a shame," he lamented. "I think some of the things that are thrown around to discredit scientists are just flat-out preposterous."
Hours after the monsoon tease seemed to have fizzled, I was awakened by an alarming but vaguely familiar percussive sound. No, it wasn't the bogeyman breaking into my house—it was thunder rattling the windows, followed by blessed rain pattering on the skylight. Suddenly, the swamp cooler smelled like a swamp again, and I drifted into a pleasant dream of a monsoon megastorm engulfing a skyscraper full of fossil-fuel executives ...