Archive for the ‘Rain’ Category

h1

Right now!

March 11, 2015

If you want to see amazing flowers in the desert, early March is the peak time.

Brittle bush and chuparosaChuparosa, palo verde, brittle bush, globe mallow, and many more shrubs have been in full bloom for several weeks now. The agaves are starting to blossom. Annuals are flowering, the spectacular poppies and lupines, as are the interesting little “belly plants,”called that by the researchers and photographers, who have to crawl around on their bellies to study the small ground-hugging plants that sprout, flower, and die back in a matter of weeks.

In lower and hotter elevations, plants bloom sooner. As the season progresses, the active blossoming moves uphill and to the north. Generally, cacti are some of the last to blossom, even out into May.

To take photographs, most people tend to go on a sunny day for brilliant, crisp flower photos. If you can, try taking pictures on an overcast day, or early morning or evening twilight for smooth even light–good for catching details that might be obscured by shadows, and capturing subtle colors.

And if you are lucky enough to get a rainy day, you have a chance for amazing photos, saturated cool colors, and moist, dripping petals on plants which rarely see moist and dripping days.

Check this websigte for useful desert flower photography tips: http://azstateparks.com/rangercam2015/index-3.html

For a list of what is blooming and where in Arizona, check out the Arizona State Parks website: http://azstateparks.com/rangercam2015/index-2.html

And the Desert Botanical Gardens website: http://www.dbg.org/gardening-horticulture/wildflower-infosite

Advertisements
h1

Too Wet!

January 9, 2015

A surprising limiting factor in some parts of the desert is too much moisture.

Wait, you say, I thought deserts were too dry?

Because there’s usually so little rain, nobody is really prepared for much. So even what might be considered a light rain elsewhere can be enough to flood out desert burrows, nests, hollows, and lowlands. If you are a creature who can move fast, or a plant that can hold its breath, you will get through it.

But even in the desert, rain is not always light. During the summer monsoon months, and a few other times of year, there can be heavy downpours.

And adding to the effect, there’s that old caliche we talked about before. This is the impervious layer of minerals and clay that forms over time a short distance down under the desert surface, and acts as a water-trap. The water can’t sink in–so where it can, it slides off downhill.

With a light rain, you can suddenly get a flash flood. With a heavy, or extended rain, you can get massive dangerous flooding, the kind that kills animals, large as well as small, and washes away trees and cars and buildings.

In the middle of many human habitations in the desert, you will find long empty wild spaces, often called “washes.” These are where the flash floods wash through, carrying away whatever is in their path.

It’s strange, when you think about it, how moisture could be a problem, and a limiting factor, in both directions in the desert.

Or maybe not. Because a lot of living things want conditions that are not too much, or too little. Instead, they want things to be generally within an agreeable range. So when you look at a limiting factor, it can be fun to check if there is another one lurking at the opposite side. Yet another mystery.

h1

Adiabatic—a what?

October 28, 2014

If you listen to the explanations given by weather forecasters, you may have heard the word adiabatic.

No, it’s not a disease related to blood sugat—that has a BET in the middle, not a BAT.

Instead, it is one very cool reason that storms suddenly pop up out of a clear sky in the desert.

Adiabatic cooling or warming happens when the pressure on a blob of air increases or decreases. When desert air hits a mountainside and rushes up the mountain, the air expands, gets “thinner” and cools as it rises to a higher elevation.

This means that if there is any moisture in the air, there is less energy to keep it suspended, so the moisture is more likely to condense, and form rain.

The opposite happens when air flows downslope—it warms as the pressure increases because the molecules are closer together and bump into each other more.

Adiabatic air activity over mountains

Maybe that is one reason that places east of mountains in North America are often more warm and dry than places to the west of mountains. Not only does the moisture get wrung out of the air on the western upslope, even very wet air from the ocean, but following that, some of the moisture on the downslope gets absorbed back into the falling, compressing, warming air.

Cool!

Or rather, cool, then warmer and drier!

 

h1

New Desert Creatures Mysteries e-book

August 12, 2014

1121d9cf157622110548bada2db9edc0c3d9d39c

Now you can get a great Desert Creatures Mysteries e-book.

It goes into detail about the strange animals of the desert, and some of the cool science about them.

https://www.smashwords.com/books/view/455225

h1

A Dry Heat

June 29, 2011

The joke is, in the Sonoran desert, even though it’s 114, it’s a dry heat.

The idea being that with very low humidity, amazingly, under 5 percent at times, the heat is easier to bear.

114, an average high for a few days each summer, is still bad enough, but given how few trees and other shelter there is in the desert, it’s almost always a sunny heat during the daytime, which adds another 7 to 10 degrees.

All plants and animals and people that live in the desert need to be built or adapt in some way to survive these extreme temperatures.

The hottest time of year is a few days before the summer Solstice on June 21, and a few weeks after that. Then the average daily temperature starts going down again, very very gradually.

A few weeks after the solstice is also the time when the summer monsoons really get going. The standard definition of monsoon season is the change in the wind, but in the desert, the important thing is that the monsoon usually brings moisture and finally rain from the Gulf of California and the Gulf of Mexico.

And of course, when the humidity goes up and the rains start, it’s still over 100 degrees in the desert. And it’s no longer a dry heat.

h1

What are Desert Wetlands?

July 15, 2010

The definition of desert is a dry place. So what do you mean, desert wetlands? Like most things in nature, deserts are more complicated, and interesting, that you’d think at first.

For example, there are many kinds of wetlands found in or near deserts:
Ponds
Freshwater and Salt or Alkaline lakes, like the Great Salt Lake
Springs and Seeps
Creeks, Streams and Rivers
Intermittent Streams, like the Hassayampa River
Disappearing Streams, like the Hassayampa River
Canals, Impoundments and other built wetlands
Oceans

Because they are such a distinct change or edge, they often host a surprising variety to wildlife, including disjunct species, that is, organisms typically found in distant areas.

This also means that they are often good places to view wildlife.