Community, Meteorology

Blessed Rain

It isn’t perfect, but it is improving.  My alfalfa seedlings are recovering from the long dry spell – on the other hand the deer are discovering them and trying to graze them down.  NOAA shows this map for soil moisture:

This next map shows precipitation during August – again, it isn’t perfect, but coming out of a drought it shows us on the fringe of recovery – far ahead of southeast Washington down through most of Oregon and California.

It may be too early to say that we dodged the bullet for another month or so – but at least the recent precipitation has moved us to a place where we can dodge. At least the long-term predictions are pretty much back to normal probabilities of precipitation:

Community, Meteorology

What Last Week’s Rains Did for Us

These maps, taken from NOAA’s website show what the early August rains did to change the moisture stored in our soil.  For us, the rains lifted the pond by almost an inch and a half.  They didn’t add enough soil moisture to fill the cracks in the vertisols, or create any puddles – but we have hopes that the slight increase in soil moisture will help at least some of the little alfalfa plants survive. At any rate, the NOAA website demonstrates how much more information on weather is available now compared to a half-century ago.  The difference between July 31 and August 9 is impressive – though we will probably check again next week to see how the soil is doing.

Community, Meteorology

The Weatherman Said

It looks like we’re into some near record or even record breaking high temperatures.  Kalispell’s record high was 105 degrees back in 1961.  I probably handled that by heading into the creek.  Still, that’s fairly gentle, compared to Glendive in 1893, or Medicine Lake in 1937 – both of which saw 117 degrees. 

As I look at the predictions for the next few days, my mind goes back to the concept of growing degree days, and then to the temperature limits on plant growth.  Corn, for example, doesn’t grow unless the temperature is at least 50 degrees, and anything over 86 is wasted.  Today’s heat isn’t much help for the sweet corn in the garden.  Wheat, as I recall handles temperatures up to 90 – but there isn’t much good to be said about 100+ degree weather for crops or people.  Alfalfa doesn’t notice the temperature until it tops 104.  (All of this is from memory, and the last time I taught the class was 35 years ago – I don’t believe that I’ve lost it since then, but checking the numbers won’t hurt my feelings)

The excess temperature has the spinach, broccoli, cauliflower, lettuce and similar leafy greens bolting – going into seed production early.  I’m not sure how the early heat is going to affect the tomatoes and peppers this early in their growth.

Still, I’ve been through the hottest day Montana could offer – I was manning a target so we could tie in two separate benchmarks on two separate mountains . . . the kind of job a monkey with passable radio discipline could handle.  I’d figured on waiting for the radio call to shift the target, then napping in the shade.  When I got to the only shade available, I saw a rattlesnake slide into a crack in the boulder I had planned to use as a back rest.  It was a shady, smooth boulder – and if I had gotten there 5 minutes later, I would have probably got the nap.  Instead, I stood in the sunlight.  There’s a word for fear of snakes.

Community

Heat Exhaustion and Heatstroke

With the weather warming, it’s time to start thinking about heat exhaustion and heatstroke. Heatstroke is the more severe condition. Heat exhaustion usually comes before the heatstroke.

Why avoid heatstroke? The short answer is that it can be fatal.

Heatstroke, also called sunstroke, is the condition of having a core body temperature greater than 104 degrees Fahrenheit. This is dangerous for much the same reason that fevers are dangerous.

The proteins that make us up are folded into very specific shapes- and need to be in order to function. When heated, proteins unfold or denature. When cooled, they don’t always go back to their previous shape (in the same way that cooling an egg does not uncook it). This is why rapid treatment is important with heat stroke- long term organ damage and death are possibilities.

Symptoms of that very high body temperature? Nausea, seizures, confusion, heavy sweating (or sweating that has stopped), loss of consciousness, fast heart rate.

Heatstroke doesn’t typically happen out of the blue. It’s preceded by other heat related illnesses. Fainting due to heat, heat cramps, and heat exhaustion can all come before heatstroke. While the lesser heat induced illnesses are all treated by moving somewhere cooler, drinking fluids, and perhaps a cold bath… drinking water isn’t suggested for heatstroke. The reason for this seems to be that people suffering heatstroke may not be able to swallow safely. It isn’t that someone with heatstroke shouldn’t be given water -but keeping them from choking should be a consideration.

Heat exhaustion shares some symptoms with heatstroke. The difference matters, since heatstroke means medical attention is a necessity. Heat exhaustion can include a weak and rapid pulse, profuse sweating, headache, muscle cramping, and skin that is cool and clammy (potentially even with goosebumps) regardless of extreme heat.

While fainting can be a symptom of head exhaustion, first symptom of heatstroke is often fainting. Unconsciousness that lasts for more than a few seconds is cause for concern. At the transition from heat exhaustion to heatstroke, sweating decreases and skin changes from cool, pale and clammy to warm and red. As sweat evaporates and is not replaced, the skin becomes dry.

Who’s vulnerable? The young and the elderly, but also anyone outside exerting themselves when it is hot. Additionally, anyone not accustomed to hot weather- which, since acclimatizing typically takes several weeks, probably describes many of us right now.

So, take it easy. Stay inside during the warmest parts of the day. Drink lots of water to avoid dehydration (not the same as heatstroke, but a contributing factor and dangerous in its own right). Keep an eye on your friends and neighbors, and if they’re starting to look like they aren’t feeling so well, get them some rest somewhere cool and keep them company. If someone suffering heat exhaustion isn’t improving once they’ve had a chance to cool down, hydrate, and rest, it’s time to consider medical attention. Heat induced illness isn’t something to take lightly.

A Science for Everyone, Meteorology

Windchill

It’s not really that cold out, is it?

Are you asking the thermometer? To a chemist or a physicist, temperature is really just a measure of how fast the molecules that make up air are moving, how much energy they have.

To those of us more interested in what the thermometer says outside, temperature has more to do with the rate at which we exchange heat with the environment. At the same temperature, a metal spoon will feel hotter than a wooden one; The metal spoon, being metal and thus more conductive exchanges heat with us at a faster rate, and so feels hotter.

Cold works the same way. The faster we lose heat, the colder it feels, even if the reading on the thermometer hasn’t gone down any.

Windchill, then, has to do with the way wind changes the rate at which we exchange heat with the air around us, specifically the rate at which we lose heat.

It makes an obvious sort of sense. The more wind, the more particles of air move by us, the more opportunities for particles of air to get a little warmer and us to get a little colder. But it’s actually worse. Wind will strip away that nice little layer of air you’ve already exchanged some heat with. It’s slightly warmer (which means its taking slightly less of your heat) and keeping all that really cold air from touching your skin. Insulating. Wind strips away that insulating layer of air.

Windchill, while ostensibly a measure of how cold it feels, is really a measure of heat loss. At it turns out, your body cares far more about how cold it feels than how cold the thermometer reads. While your skin temperature isn’t going to drop below ambient temperature, your body will perceive things as colder than they are, and respond accordingly. Frostbite? Hypothermia? The symptoms of those are the result of the body responding to how cold it feels.

Thirty degrees and windy can’t actually drop your skin’s temperature below thirty, but it’ll feel colder, and that is enough to increase the risk of cold related injury such as frostbite. While the equations to calculate windchill vary a bit, windchill warnings are serious business.

It’s not really that cold out, is it? Not if you ask the thermometer. If you’re asking me, however…

Community

Dust Devils and Whirlwinds

Strong swirling winds, but over a small area. Spinning dust and debris. Brief, often a handful of minutes. Almost out of nowhere on a warm, clear day.

The literature that studies them calls them dust devils, but to the people that live with them they are dust whirls, whirlwinds, sand trumpets, sand hoses, devils and spirits. In Australia, one might be called a Willy-Willy. In Ireland, a “sí gaoithe“, which translates to something along the lines of “fairy wind“.

They don’t actually require dust or sand. Dust and sand do serve to make these sudden little whirlwinds visible, but they aren’t a requirement. In fact, the whirlwind need not be visible at all.

And they are whirlwinds. Small and brief whirlwinds, to be sure, but whirlwinds none the less. While they appear somewhat akin to a tornado, the formation is somewhat different. A dust devil is generally the product of a warm day with clear skies.

We had another one through recently, resulting in some impressive destruction in a small area. It happens on a warm day, when the sun heats up an area on the ground (asphalt and other dark surfaces heat up more) and that hot air rises. Then, cooler air from nearby rushes in to fill it. A spinning motion forms, and a dust devil is born.

So where are these likely to happen? In areas where heating occurs beside places which will be cooler. Perhaps because they are shaded, perhaps because they are near water, perhaps simply because a nearby lawn has recently been watered and is cool.

Where do they go once formed? In the direction a light breeze pushes them, up hills but not down them. They will cross water and travel through forests (Benjamin Franklin wrote an account of one doing that). Sometimes, though this is less common, they stay in place.

The general gist is that dust devils are going to be more common in some areas than others, based on the local conditions and landscape. They’re generally going to follow similar routes and stay moving. Landscaping may present some potential for shielding buildings that are routinely hit by them. While these little whirlwinds could theoretically last most of a day, they’ll typically disperse within 5 minutes. Dust devils are found across the world and usually do not cause major damage to people or structures.

Also, if anyone thought the reading was boring, it turns out that the early studies to determine maximum wind speed in dust devils involving dropping kangaroo rats from two and three story buildings. The rats were apparently angry, but unharmed. If you’re interested in the particulars, you can find them towards the end of the fifth page in the pdf. Enjoy!