Archive for March, 2014

Before It’s Gone, A Primer on Snow

Any skier or snowboarder knows that snow does not come in just one form.  Snowpacks are as variable as the snowflakes that form them.  We have all heard the claim that Eskimos have dozens of words for snow (actually, I discovered, just more flexibility in how root words are modified), but what about our terms for snow?  Skiers talk about corduroy and corn snow, but the variation in snow types extends beyond the ski slopes. 

601124_677097335993_631112764_nHere is your late-in-the-season glossary of snow.  Maybe your optimism tells you that the snow won’t be with us much longer, but it might be in your best interest to brush up, just in case.

Snow forms when the atmospheric temperature is at or below freezing.  In certain conditions, it is even possible for snow to reach the ground when the ground temperature is 41 degrees Fahrenheit.  Freezing atmospheric temperatures, combined with moisture in the air, forms snow crystals.  Snow crystals exist in four forms: snowflakes, hoarfrost, graupel, and polycrystals.

  • Snowflakes, which we are all familiar with, are clusters of ice crystals that fall from clouds.  Their shape is dependent on the conditions in which they are formed and through which they fall.
  • Hoarfrost is our name for ice crystals that form on small surfaces that are open to the air.  When a surface’s temperature is lower than the frost point of the surrounding air, moisture transforms directly from vapor to solid, forming delicate laces of surficial ice.
  • Graupel is the round, pellet-like snow that resembles a softer hail.  When ice crystals fall through super-cooled cloud droplets (which remain liquid although they are below freezing temperatures), the droplets freeze to the crystals, forming a clump.
  • Polycrystals are flakes made up of many individual crystals.

The National Snow and Ice Data Center has gone one step further and categorized the types of snow cover, or snowpack.  Snowpack is defined as all the snow and ice that lies on the ground at a given time, including fresh snow and any older snow still on the ground.  Its composition is affected by air and ground temperatures, temperature stability, wind, and the length of time that snow stays on the ground.  The six types of snowpack are: new snow, firn, névé, old snow, perennial snow, and powder snow.

  • New snow is snow that accumulated recently enough that the original form of its ice crystals is still recognizable, as when snowflakes’ delicate shapes are still visible on top of a layer of fresh pow.
  • Firn is snowpack older than one year.  It is dense and well-bonded.
  • Névé is young, granular snow that has been partially melted and then refrozen.  This process hardens and compacts it.  If névé lasts longer than a year, it becomes firn.  This is the main snowpack type resulting in glacier formation.
  • Old snow has been transformed enough that its ice crystals’ original form is not recognizable.  The amount of time new snow takes to become old snow depends on a number of factors.
  • Perennial snow, as its name suggests, is snowpack that never melts but stays on the ground year after year.
  • Powder snow is fresh, dry snow comprised of loose crystals.

Consider this the next time a friend invites you to hit the slopes.  Is it really powder you’re carving or is it old snow?

Don’t even get me started on the different types of snowfall (blizzard, snowstorm, snow flurry, snow squall, snowburst, blowing snow, drifting snow).

Winter Blooms

By Matt Pierle


Cabin fever have you ready to see flowers again? If so, you’ve got options: Brazil and Bali are nice this time of year. Or seek out plants at a world-class botanical conservatory in, say, Montreal, London or San Francisco.

If you’re short on time or prefer shoestring travel though, you could do what I did over spring (technically late winter) break and book a $26 ticket on the Megabus from Burlington to Boston. From South Station Boston walk north to Chinatown, through Boston Common, past the frozen Frog Pond, to the Longfellow Bridge, over the Charles River to Cambridge and kick it up Broadway to Harvard Street. Continue north all the way to the Harvard Museum of Natural History.

In bloom you’ll find the extensive Ware Collection of Glass Models of Plants created by Czech born Leopold Blaschka and his son Rudolf. Most people simply call the collection “The Glass Flowers.” You read that right. This collection is not of flowers under glass, it is of flowers made of glass.

These life-size and larger-than-life specimens are more than impressionistic representations of garden blossoms; they are über-accurate botanical sculptures of a diversity of wild and cultivated plants. The pieces will challenge your powers to believe that something so realistic could be made from inert, colored sand.


Who were the Blaschkas? How did they do it? And how did Harvard acquire these pieces?

The Blaschkas’ craft was not glassblowing. These pieces were created through a process called flameworking or lampworking. Glass rods were heated with the aid of paraffin and alcohol lamps, then cut with specialized scissors and shaped with tweezers, prods and other tools. Fine cooper wire provides structure for some of the daintier botanical structures, although I never once noticed the hidden metal armatures. Originally the pair worked with clear glass and then painted the models. Later they employed colored glass from the get go. Their eye for color was refined, to say the least, and a hundred or so years of display at the museum does not seem to have compromised their luster.

The artists, who worked without assistants or apprentices, came from a strong tradition of glasswork, a trade well established in their native Czech Republic. Indeed, Leopold’s father had also been a glassmaker. After Rudolf’s birth in 1857 Leopold moved the family to Dresden and established a workshop there.

From as early as 1863, Leopold earned a reputation for crafting museum quality glass invertebrates, mostly marine inverts, everything from jellyfish, and mollusks to sponges and corals.  The lifelike pieces were and are held by universities, museums and aquaria the world over – a few of which can also be seen at the Harvard Museum of Comparative Zoology.


Leopold Blaschka experimented with plant models between 1860-1862 prior to making the marine models. These early plant models went from one owner to another before eventually being destroyed in a museum fire in the city of Liege, Belgium. In 1876 Rudolf started working full-time with his father. The Blaschkas spent the next ten years focusing on marine works for until they were approached by Dr. George L. Goodale who asked them them to make a few glass plants for Harvard.

Dr. Goodale was a plant physiologist and then curator of the herbarium at Harvard. After becaming familiar with the Blaschka’s impeccable work he traveled to Europe to meet them. Goodall wanted to have plant models that would endure for teaching and demonstration purposes. The Blaschkas shipped some pieces to the U.S. on speculation. In spite of being damaged in New York by customs inspection, Goodale showed the floral pieces to the Elizabeth Ware and her daughter Mary. The Ware women were sufficiently impressed. They generously offered to fund all aspects of the artistic production of more plants in honor of their late husband and father Dr. Charles Ware, a graduate of Harvard Medical School.

According to Jennifer Brown, the collection manager, Goodale hoped there would be at least 50 pieces created. That was 1886. Over the next 50 years the father-son team produced for Harvard around 4,300 individual pieces representing 787 distinct plant species.

The pair worked from plant specimens and cuttings sent from Harvard, from live material planted around their estate and from botanical drawings. While Leopold Blaschka remained in Europe, Rudolf traveled to the Americas in 1892 and then again in 1895. On those trips, he visited the growing collection of glass flowers at Harvard and did botanical drawings in the U.S. and Jamaica.

Packed in cardboard boxes with tissue paper and excelsior (wood wool), surprisingly few pieces were damaged in transport across the Atlantic from Germany to the U.S.


At Harvard, the glass flowers are displayed in the style of herbarium vouchers

Each plant’s common and Linnaean name is shown on a tag, and smaller tags interpret oversized plant parts along with the degree of magnification (two to several hundred times). In this way, plant structures not easily seen with the naked eye are clearly displayed.

Peer into the throat of an iris to see the fine hairs lining the inner surface of the petals. See how the Nerf-football-sized male flower of a bat-pollinated banana plant dwarfs the dozens of female flowers that will develop one of our most globally important fruits.

Along with floral structures and fruiting bodies and non-reproductive plant parts like roots, leaf buds, and trichomes are presented in all of their fine scale glory.

Because of Harvard faculty interests in economic botany, later productions by the Blaschkas focused on cultivated plants from palms to figs, and from coffee to cacao.

There is even a rotting fruit series that depicts in jaw dropping accuracy stone fruits with fungus damage and apple fruit with cutaneous scab infections. Pieces emphasizing pollination feature flowers lacking one or more petals in order to show in graphic detail how foraging bees facilitating the transfer of male gametes from one plant to another.


Exquisitely lifelike and, even to a botanist’s eye, beyond botanical reproach, the glass flowers will at once delight and educate you

Delicate flowers, tangles of roots and fresh leaves are all created as if by cloning. Goodale’s interest in having a collection of precise teaching specimens has been realized.

While several glass artists have tried, no one has replicating the exacting accuracy that the Blaschkas achieved. It’s not surprising that people arrive to Cambridge from all over the world to see these masterpieces and that many suggest that a divine energy or touch must have guided their creations.

If you’re a lover of plants, sculpture or hyper-realistic art, this is a collection you’ll want to see for yourself. Kids to seasoned botanists alike will appreciate the gallery, and the nice thing is, no matter which month you visit, the glass flowers are guaranteed to be in bloom.

Right now, it could be the perfect cure for cabin fever.




Matt Pierle is a Field Naturalist candidate at the University of Vermont who has botanized from California to Cambridge. 

Special thanks to Collection Manager, Jennifer Brown, Herbarium Co-Director, Dr. Charles Davis and Gallery Volunteer, David Donovan. All photos by Matt Pierle with permission from the Harvard University Herbaria and Harvard Museum of Natural History.