A late spring, early summer, when-will-it-end drought is currently making our lives miserable in many parts of Virginia.
In my county we’ve ticked up to ‘severe drought’ status. This is better than ‘extreme,’ and not as good as ‘moderate;’ but most of us are just referring to it as the summer we decided to give up on our hopes and dreams and pray for the onset of winter.
And as it’s the election year – possibly The Sweet Meteor O’ Death too.
High temperatures in the region for weeks have also contributed to a general pissed-offedness. If you have friends or relatives who work outside professionally, it may be best to avoid them until you see the first Pumpkin Latte in your Instagram feed.
Don’t forget to add relative humidity my California friends…
Just in case you need that in Celsius…
Curious to see if what I was feeling matched what was actually happening, I got up close and personal this week with the U.S. Drought Portal — a website managed by NOAA’s National Integrated Drought Information System (NIDIS) – to get some stats on this drought and our historical episodes of drought. A fascinating dive – no pun intended.
As they say on the site (and as I can confirm as a native Californian relocated to Virginia) “Drought in Maine looks very different than drought in New Mexico.”
Making Sense of Terms
Drought is more complicated than ‘Has it rained, and how much?’ That’s meteorological drought, and the number we instinctively look up while surveying our crispy hostas, but a better definition of drought is the imbalance between water supply (precipitation) and water demand (evapotranspiration). On a very basic level, as temperatures increase, so does demand. We’re living that in Virginia right now.
You know it’s bad when the Geranium macrorrhizum is browning
In terms of meteorological drought and rainfall, the words ‘normal’ and ‘abnormal’ are also difficult terms to wrestle with as a layperson. The latter is not only a matter of scientific fact (how many hundredths of an inch we are deviating from mean precipitation, i.e. ‘normal’), but an instant pejorative.
‘Abnormal’ feels frightening and foreboding, even if we realize somewhere in the back of our minds that we are dealing with precipitation averages — and averages need ranges to be calculated in the first place.
The Standard Precipitation Index (SPI) was developed in the early nineties to more accurately quantify that number for various regions over specific time periods using data going back to 1895. This gives us rankings such as “driest (or wettest) on record” or the words “record breaking” — which are eagerly pounced upon by news platforms looking for stories to keep us up at night, but it is not without its weaknesses as it is a indexed measurement of precipitation only.
Some plants are hanging tough – In terracotta no less! Carex x ‘Feather Falls’
Swimming Through Statistics
You can break a record by one one-hundredths of an inch that stretches back to records set 100 years ago – or merely 5. Which is not to downplay how valuable these data are, but to help us accurately and calmly navigate them.
For instance, June was our driest June in Virginia since precipitation was first recorded in 1895. Conversely, May only ranked 105th driest in the same 129 years. The driest May happened in 1911. The driest April in 1942. And in the period between January and our driest June ever, the state of Virginia is actually up in measurable rainfall by seven tenths of an inch.
That doesn’t make us feel better about our hostas of course, because it’s also not the whole story.
As fascinating as this chart is, it only shows one aspect of drought – historical precipitation.
What these data can’t show you is all the other variables such as “rainfall, streamflow, groundwater levels, regional climate, soil moisture, water storage in reservoirs, ecological conditions, municipal water restrictions, and the time of year” (according to NIDIS). These are evaluated on a weekly basis to come up with the US Drought Monitor Map.
That’s an incredibly handy tool to more accurately assess what we’re dealing with, but sadly, that number crunching only goes back 24 years to 2000.
And More Statistics….
There are thoughts that a newer (2010) Standard Precipitation Index – the SPEI — might be able to model evapotranspiration from 120 years of historical data (since 1900), and successfully pair them with precipitation data to come up with a more complete picture.
I’m interested to know why it hasn’t been adopted by NIDIS yet. Perhaps (and this is most likely a gross over generalization), there are just too many values within the datasets to provide an accurate picture? We’re talking about averages of sun hours, wind speed, cloud cover, temperature, relative humidity, solar radiation, etc. – all plugged into a function and tied to another function.
And my guess is, that such a feat is one thing when, in the year 2000, scientists get together and begin to gather the same data in the same way across agreed upon geographical points (hence the Drought Monitor Map); but very different when we have to go back and dodge gaps in historical data.
I don’t know, but I do know that the math is definitely beyond my college statistics class.
Patterns of Drought Encourage Adaptable Plants – And Gardeners
Beyond statistics (which you can very quickly find yourself clicking through for hours) I very much appreciate the neutral but specific language that much of this site employs.
“Drought is a normal climate pattern that has occurred in varying degrees of length, severity, and size throughout history.” says the NIDIS, and boy they’re not kidding. Examining the handily graphed SPI data for Virginia going back to 1895, it looks as if our major issues of precipitation often have more to do with too much rain than too little.
Regardless, it was a very good dive, and I heartily recommend you have a look for your state. You can view 24 years of the Drought Monitor Map, or 129 of the SPI. Or you can even look at Paleoclimate data reconstructed from tree ring studies.
I did not come away feeling happy about the current drought, but more capable of putting it into historical perspective. That energizes me to be adaptable and plant for new patterns, rather than give up the ghost and shake my fist at the sky.
I’ll save that for the election. – MW
Very interesting article. I looked into my state’s stats and signed up for their email alerts. Hate to brag but we’ve had over an inch of rain per day for the past two days due to thunderstorms. However, most of the garden is lying flat on the ground now… This is the earliest I have ever hoped for frost to end it all.
Thank you – I’m glad you found it helpful. I too signed up for their email alerts. And yes, you’re bragging. – MW
Very interesting article. Thank you. I must note however that pernicious weeds and invasive vines, growing from cement like hard-pan seem quite undeterred. And the miserable little mammals we thought we’d effectively excluded sashayed in and ate every last morsel in the veggie garden. Never happened before in 48 years in this garden. Despite incredible level of work in the orchard on part of younger son, to revive elder apple trees with regenerative practices- things look grim out there too. My challenge is to persuade elder husband that this is not a one off situation and to change ambitions and planting approaches, esp for trees and woody shrubs. In our recent visit to Kew Gardens and Wisley, the plantings have changed profoundly for this new reality. We must indeed adapt.
As much as I hate those pernicious weeds and vines, I can’t help but be amazed that there is always something that will spring from baked cement. A testament somehow to the Earth’s resiliency. That of course doesn’t make weeding them out any easier. But OMG the WHOLE veg garden? I am so sorry. After so much effort in deer fencing, it is just heartbreaking. – MW
As a professional gardener, you got that right, yes i get grumpy, and miserable. The hotter & drier, the more i’m staggering around in the heat, dragging hoses. I grew up hearing from my mother, about the Dust Bowl, when everyone’s wells dried up, and they had to slaughter so many animals, no water, no feed…..so that was the stuff of my nightmares, when i was young…..and those dreams still haunt me.
Karen – did you look at the stats and words about the dustbowl era? That still tops the historical record. 68% of the lower 48 were in drought. “While recent droughts and heat waves have made news and broken records in some areas of the United States, by the size of the geographical area affected and the length of time that it persisted, the Dust Bowl era of the 1930s is still the most notable drought and extreme heat event in the U.S. historical record.” (from drought.gov) – so your mother’s memories were not inflated and your nightmares had basis in terrible fact. Those of us on wells always chew our nails a little bit — particularly in western states. – MW
Welcome to my world…’Feather Falls’ is a rock star. Beautifully researched article. We had rain a couple of days ago-hope it comes your way.
Got a 1/4 inch on Thursday in the afternoon. I’ll take it! – MW
And less than 200 miles to the southeastern part of the state we are listed on the Drought Monitor Map as “None”. We had a hot and dry stretch for about a month that was getting frustrating but then wide-spread thundershowers have come through over the last few weeks. We now have a 50% to 60% chance of rain each of the next six days. I see north-west VA also has a good chance of rain so maybe you will finally get your share and the majority of your plants can recover. I have lived in Va for most of 68 years and I have seen my share of hot, dry, hose-dragging summers, as well as unusually wet ones where the crab grass grows half a foot overnight. I know the climate is changing, but unlike the mainstream media, which seems to tack on the phrase “due to climate change” at the end of every other sentence, I’m not ready to declare hot and dry as the new normal. Just a stuck weather pattern which is quite normal in summer, and also happens in winter.
That’s why I was thankful to this site for the neutrality of data, the transparency in how it is collected and parsed, and the emphasis that drought is a natural climatic occurrence. ‘The new normal’ is likely to be different for all of us, with new patterns in our gardens and our seasons; and reductionist statements as loved by news outlets do not come close to telling the story.
Whatever our patterns are, we should navigate them with positive solutions, not gloom and doom and ‘why bother!’ Clean and transparent data help a great deal in figuring it all out. Thanks for your thoughts as a fellow Virginian. (Or do I get to call myself that as a transplant to Northern Virginia? LOL) – MW
I spent my growing up years summering at Colonial Beach VA. (in the 50’s). We did not have A/C and only 1 fan in the kitchen which was on the west side of the house. In spite of the Potomac River being almost at our doorstep little breeze was noticed, and certainly none after 5 pm. All sailors knew to be at the dock if being home for dinner was important by 5 as that was when the wind died. In July we always had 3-4 days in a row when the temp was 103-5 degrees. Actual temps, not humidity increased! During those days sailing didn’t take place as there was NO wind! The occasional 100 degrees now in central VA just seems, well normal! I never look at what the weather folks tell me will be coming….as a sailor I can tell better by reading the sky. And my garden (the 4th I have had over the years) seems to be the same more or less, year to year. Some years they are great and others not so much! The graph was interesting and does show that we often remember erroneously!