Sunday, February 28, 2016


This text is from Mario Rigoni Stern.  English translation by Joseph E. Tomasi. When translating he wrote to me from Ulaabaatoar, Mongolia, where he lives, that it was snowing, and all was covered by ten-twenty centimetres of white. He wrote: "According to Rigoni-Stern's calendar, it would be a bàchtalasneea, but according to the local season, it is more probable a swalbasneea. They were the right days to translate Nevi. "


There are many snows in my memory: the snows of avalanches, the snows of high altitudes, the snows of Albanian mountains, of Russian steppes, of Polish moors. But it is not of these that I wish to speak; I will speak instead of how snows were once called where I come from: snows with many names, snows of yesteryear, ignored by the weather reports of winter sports resorts.
Brüskalan is what Old Auntie Marietta, my grandfather’s aunt, would say to me; that was the first snow of winter, the real stuff. It could snow and snow even in October and November, but autumn snow is weak snow, limp snow, which hinders the grazing of cattle in meadows mowed in September and the work of the woodsmen when the ground is not yet frozen in the woods. I remember the nuisance it would cause on All Souls’ Day, when tin garlands and real ferns from the woods would drip snow on newly cleaned graves; and how in the woods not yet completely bare we would go to cut beech trees: how grudgingly we worked with hands a-freezing, and how the snow stuck to our boots. There I learned that wet snow chills more than powdery snow. 
But when the brüskalan came it was different. After the Indian Summer, after Martinmas, the earth was well frozen, noisy under our hobnailed boots with studs and spikes. The smell of the first snow filled the air:  a clean and light smell; better and more welcome than the smell of fog. The healthy fog, I mean, the one that would come one or twice a year about the time of the migration of the skylarks.
Raising your gaze to the north, you would see a faint greyness that from the peaks reached low to the woods and then came down towards the town. And the top of the bell tower and its bells were soon within the grey milkiness and then the whole church, the roofs of the highest houses too. On the dusty streets, on the log piles, in the courtyards, and onto our ruffled heads the first flakes fell. We would open our mouth skywards to feel them melt on our tongue.
Very soon the snow would cover the dusty streets, the dry grass in the meadows, the sawdust in the courtyards from the beeches, the graves in the cemetery.
The voices and sounds of the town, the calls of sparrows and wrens became muffled, and at this point the brüskalan became real sneea: snow abundant and light coming down from the mill in the sky. Then, with trepidation, we would go up to the attic to find skis and lame (blades), our one-man sleds: in Scandinavia I have found identical objects with an identical name that, however, has no relation to the Italian word lama.  
We skied and sledded on the road  leading down to the main square, defying the local policeman and the scoldings of mothers and grandmothers, who, on their way to Mass, were slipping on hardened snow, bound  to become bare ice that not even the snow plow pulled by twelve horses would be able to scrape away.
This is more than seventy years ago. I must have been about five years old when an uncle of mine, who had been with the Alpini troops from 1913 till 1920, tied two curved lengths of wood to my boots, which he called skj, and I hurtled myself down the piste, which was then no more than the snow piled in front of the house by the snowplow and from the clearing of the courtyards: a nice big pile that covered the fences and gate pillars and that to us children seemed very high indeed. With spades and cinder shovels we smoothed its descent to the road; to climb up it, we dug steps right into it: - Make waaay!
But then the winter would wear on; the wood stocks would thin because the fireplace ate and ate; as did the stove in the kitchen. My grandfather's chair was near the stove, and it was there that he loved to smoke his pipe and, when I would come home all wet and cold, I would go between his chair and the stove to put my back against the warmth. Auntie would grumble, saying that I would cook my blood.
As winter wore on towards its end, the sneea became haapar. On the riverbanks in the sun it would trickle away over the earth in thousands and thousands of drops, and the brown of the soil would appear. It was at this time of year that we would hear the first skylarks: suddenly one morning a shiver would run over your skin and it would be their song, high in the sky above the haapar
With the haapar came the haarnust. That is the old snow that in springtime, during the warm hours, the sun softens at the surface and then the cold of the night hardens again. Excellent snow for off-track excursions, to be done from the very first light of dawn until about eleven in the morning, in every terrain and with cross-country or mountaineering skis, with good klister grip wax or skins. But even on foot, when because of our age we were not to take risks. Then we would walk with comfortable lightweight boots upon the haarnust, which bore the weight of our steps without giving way: we would walk "high", as if suspended over rocks and dips, level with the tops of young firs that sprout from the snow with the spring, which always started with the smell of tree resin, and on we marched effortlessly in mid-air. Then, when all the snow had melted, returning to those places, we would say: "I walked up there, at the height of those branches."
After the haapar and after the haarnust came the swalbasneea: the snow of the swallows, the snow of March that has always been on time through the centuries. It falls after the swallows have come back: sometimes soft, sometimes wet, sometimes as a blizzard, or even calmly into swollen banks. In one night it can fall up to a metre thick, and then the swallows that arrived up here to announce the spring will return to the plains for a few days, until the damp air or the rain or the pregnant soil melts the swalbasneea away. 
The kuksneea is the snow of April; it does not always come but it is not rare either. On meadows that are beginning to show green again and where the crocuses are blooming it does not last long, as the living earth melts it even before the sun can. Just as the swalbasneea is the snow of the swallow, the kuksneea is the snow of the cuckoo because it is he, the joyous awakener of the woods, who sometimes calls it, to have fun when it falls away from the branches of the conifers: for him, who comes from Africa, this thing soft and white and cold is both rare and curious.
When the meadows are covered with the solar yellow of dandelions and the blue of forget-me-nots, and the bees are busy from dawn till dusk collecting pollen and nectar, then might come the bàchtalasneea: the snow of the quail. A cloud bearing down from the north, a gust of wind, a sudden drop in temperature and in May can come the bàchtalasneea. It lasts only a few short hours, but long enough to scare the birds in the nest, to bring death to the bees surprised outside the hive, and to worry the does about to give birth.
I do not remember when exactly, I did not write it down; perhaps the last summer snow fell about fifteen years ago. I do not know the old name for this snow, I would need to ask those who now are a hundred years old or more. Perhaps they called it kuasneea: the snow of the cows, because in summer they can be found high in mountain pastures. Probably when it falls the cows come down bellowing to the woods and it becomes difficult to herd them. And making cheese becomes a problem too. The memory of this snow and when it fell lives on in the names of those born on those days: Nives, Nevino, Bianca, Nevio ...

From Sentieri sotto la neve (Paths Beneath the Snow), 1998, Mario Rigoni Stern


Ho tante nevi nella memoria: nevi di slavine, nevi di alte quote, nevi di montagne albanesi, di steppe russe, di lande polacche. Ma non di queste intendo parlare; dirò di come le nevi  un tempo venivano indicate dalle mie parti: nevi dai più nomi, nevi d’antan, non considerate nei bollettini delle stazioni degli sport invernali.
Brüskalan, mi diceva l’Amia Marietta, la zia del nonno; ed era questa era la prima neve dell’inverno, quella vera. Nevicava, nevicava, anche a ottobre e a novembre, ma la neve autunnale è una neve fiacca, flaccida, che interrompe il pascolo alle vacche sui prati falciati a settembre e il lavoro del bosco quando il terreno non è ancora gelato.  Ricordo il fastidio che dava, il giorno dei Morti, quando le ghirlande di latta e le felci vere del bosco sgocciolavano neve sulle tombe ripulite; e quando nel bosco non ancora del tutto spoglio si andava al taglio del faggio: come malvolentieri si lavorava con le mani che gelavano, e come la neve si attaccava agli scarponi. E’ così che ho imparato che la neve fradicia raggela più di quella farinosa.

Ma quando brüskalanava era diverso. Il terreno dopo l’estate di San Martino era ben gelato e risuonava sotto le scarpe chiodate con le brocche e giazzini. Lo si sentiva nell’aria l’odore della prima neve: un odore pulito, leggero; più buono e grato di quello della nebbia. Di quella nebbia sana, intendo, che veniva una o due volte all’anno al tempo del passo delle allodole.
Alzando lo sguardo verso nord vedevi un tenue grigiore che dalle cime raggiungeva i boschi e che si abbassava verso il paese. E la punta del campanile e le campane erano già dentro il grigiore lattiginoso e poi anche la chiesa, i tetti delle case più alte. Sulle strade polverose, sulle cataste di legna, sui cortili e sopra le nostre teste arruffate cadevano le prime stille. Aprivamo la bocca verso il cielo per sentirle sciogliersi sulla lingua.
In breve la neve copriva la polvere delle strade, l’erba secca sui pascoli, la segatura di faggio nei cortili, le tombe del cimitero.
Le voci, i rumori del paese, i richiami dei passeri e degli scriccioli si facevano lievi, e a questo punto la brüskalan diventava vera sneea: neve abbondante e leggera giù dal molino del cielo.
E noi si andava trepidanti in soffitta a prendere gli sci e le lame, i nostri slittini monoposto: oggetto e nome che ho trovato identici in Scandinavia e che non hanno nulla a che fare con l’italiano lama.
Si sciava e si slittava  sulla strada che scendeva verso la piazza, sfidando la guardia comunale  e le sgridate delle mamme e delle nonne, che andavano a messa e scivolavano sulla neve indurita destinata a diventare ghiaccio vivo, che nemmeno lo spazzaneve tirato da dodici cavalli sarebbe riuscito a intaccare.
Questo più di settant’anni fa. Forse avevo cinque anni quando uno zio, che era stato alpino dal 1913 al 1920, mi legò agli scarponi due tavole arcuate che si chiamavano skj e io mi buttai giù per la pista, che era poi la neve ammucchiata davanti a casa dallo spazzaneve e dalla spazzatura dei cortili: un bel mucchio che superava i recinti e i pilastri del cancello e che a noi bambini sembrava altissimo. Con i badili e le palette del focolare lo lisciavamo verso la discesa della strada; per salirci sopra avevamo scavato dei gradini: - Pistaaa!
Ma poi l’inverno diventava lungo; le scorte di legna si assottigliavano perché il focolare mangiava, mangiava; come pure mangiava la stufa nella stua. La sedia del nonno era vicina alla stufa, ed era lì che amava fumare la pipa e io, quando rientravo bagnato e infreddolito, mi mettevo tra la sedia e la stufa per appoggiare la schiena al caldo della parete. L’aria mi brontolava perché diceva che mi cucinavo il sangue.
Quando l’inverno stava per finire la sneea diventatava hapar. Sulle rive al sole andava via per la terra in mille e mille gocce, e appariva il bruno del suolo. Era in questo periodo che sentivamo le prime allodole: una mattina ti correva il brivido per la pelle ed era il loro canto alto nel cielo sopra l’haapar.
Con l’haapar veniva l’haarnust. è questa la neve vecchia che verso primavera, nelle ore calde, il sole ammorbidisce in superficie e che poi il freddo della notte indurisce. Neve ottima per escursioni fuori pista, da farsi nelle primissime luci dell’alba e fino alle undici del mattino, in ogni terreno e con gli sci da fondo o da alpinismo, con buona sciolina klister o pelli di foca. Ma anche a piedi quando pe l’età non si deve spericolare. Allora si va con comodi scarponi leggeri sopra l’haarnust che sopporta il peso del passo senza cedere: cammini in “alto” , come sospeso, sopra pietre e buche, a livello degli apici degli alberi giorni che spuntano dalla neve verso la primavera che incomincia con l’odore della resina, e vai senza fatica, a mezz’aria. Poi, quando tutta la neve sarà sciolta, ritornando su quei passi verrà da dire:”Ho camminato lassù, all’altezza di quei rami!”.
Dopo l’haapar e dopo l’haarnust veniva la swalbasneea: la neve delle rondini, la neve di marzo che è sempre puntuale nei secoli. Cade dopo che sono arrivate le rondini: a volte soffice, a volte bagnata, a volte come tormenta, o anche calma in dilatate falde. In una notte può caderne fino ad un metro e allora le rondini arrivate quassù ad annunciare la primavera se ne ritornano in pianura per qualche giorno finché l’aria umida o la pioggia o il terreno in amore non avranno sciolto la swalbasneea.
La kuksneea è la neve d’aprile; non sempre presente, ma non è nemmeno rara. Sui prati che incominciano a rinverdire e dove sono fioriti i crochi non si ferma molto, perché  prima ancora del sole la terra in amore la fa sciogliere. Come la  swalbasneea è la neve della rondine, la kuksneea è la neve del cuculo perché è lui, il gioioso uccello risvegliatole del bosco, che qualche volta la chiama per divertirsi quando di sfalda dai rami delle conifere: per lui che viene dall’Africa, questa bianca e soffice e fredda è rara e curiosa. 
Quando i prati si coprono del giallo solare dei fiori del tarassaco e dell’azzurro dei miosotidi, e le api sono indaffarate dall’alba al tramonto nella raccolta di pollini e nettari, allora può arrivare la bàchtalasneea: la neve della quaglia. Una nube che scende da nord, una ventata, un rapido abbassamento della temperatura ed ecco a maggio, la bàchtalasneea.  Dura solo poco ore, ma sufficiente per fare paura agli uccelli nel nido, dare morte alle api sorprese fuori dall’arnia e preoccupazione alle femmine di capriolo in attesa del parto. 
Non ricordo con precisione, non me lo sono annotato; forse l’ultima neve estiva è caduta una quindicina di anni fa. Non so il nome antico di questa neve, dovrei chiederlo a chi ora ha cent’anni. Forse di chiamava kuasneea: la neve delle vacche, perché d’estate si trovano sui pascoli delle malghe. Probabilmente quando viene giù le vacche scendono urlando nei boschi e diventa difficile tenerle in mandria. Come un problema diventa fare il formaggio. Di questa neve rimane memoria e data nei nati in quei giorni: Nives, Nevino, Bianca, Nevio …

Da Sentieri sotto la neve, 1998, Mario Rigoni Stern

Thursday, February 18, 2016

The man who planted trees. Part II

In a previous post, I asked if we were able to simulate the effects foreseen in the small movies, The man who planted trees (take the time to watch it, it is an experience by itself). I entitled the post: part I because I had many points to develop (and still I have). 

However, in the meantime, I was accumulating material, this review appeared (in this new Journal WIREs Water) which is pretty much on the my point of view of hydrologic modeller. Maybe some expert of ecohydrology, more expert than me, which is easy, can find some part underdeveloped. However, with its almost five hundred cited paper and its clarity, this review is certainly a good reading for anyone who wants to approach the argument.


Fatichi, S., Pappas, C., & Ivanov, V. Y. (2015). Modeling plant-water interactions: an ecohydrological overview from the cell to the global scale. Wiley Interdisciplinary Reviews: Water.

Sunday, February 14, 2016

Lanscape evolution models (LEMs)

I worked on landscape evolution twenty years ago, mainly during My Ph.D. studies. My literature reference at that time was Bill Dietrich’s one. It would be interesting to know how his collection changed in time te get it updated. My perspective moved in recent years more to Hydrology, but some of the ideas that I collected remained in the background of my mind, and informed my subsequent research. 

Looking now at it, I can say that my work on LEMs followed two main path.   

The first direction was to prove and consolidate analysis tools (my lessons, in Italian, here). These tools (in general, I mean, not specifically mine) do not have evolved much since then, if we exclude that the availability of high resolution data implied some adaptation and offered some opportunity.* They remain the first step, to assess the result of models. In the past I had the impression, that some theories had credit for the insufficient control on  geomorphic characteristics that now can be easily detected.

The second direction was to look for the processes that generate landscape evolution. In my work, the triggering mechanism was channel initiation, counteracted by hillslope-diffusive processes. The first generating fractality, the second destroyng it. However, I soon realise that, in practice, this was interesting but too simple, and certainly the process is mediated by the soil production. So, in my new hypothetical model I would put soil/sediment production in, to limit the landscape change (maybe was this the detachment limitation implied by A. Howard ?). 
The ability to produce soil would differentitate different climates/geological situations. I use both because, it seems to me, that they do not act separately. 

In any case, landscape evolution models usually do not treat  mass wasting  (see also here for other contributions) and usually the effects of the cryosphere (but I could be out-of-date on that side).  Mass wasting is threshold dependent, and the threshold depends both on soil/sediment and climate again. While in other aspects climate probably enters in the picture with  mean properties (this phrase can look a little bit weird, since climate is the supposed mean of weather ) of temperature and precipitation, mass wasting is dependent on the statistics of extreme events which cause soil/sediment failure and transport. 
On the effects of the cryosphere I remember a paper by David Montgomery on the height limits of mountains that introduced the effects of ice and glaciers (another paper is here).
So my next ingredient in the picture would be to have a statistically controlled set of precipitation (a topic on which there is great knowledge) and a set of rules for determining the triggering of mass waste events, and their magnitude. Statistics exist on that aspect that can be used appropriately. 

As I told above, on the actions of the cryosphere I do not have clear indications, but it is known that it has huge and persistent effects ( called paraglacial inheritance), which clearly we did not accounted for in our previous work. Maybe a first approximation would be to avoid glaciated area, but mountains mean, maybe not for much longer, snow and ice.

I am not forgetting to give a little  substance to Tom Dunne phrase:" it is all about climate and tectonics ". My references ob this topic are limited to a recent paper on river and tectonics, published in Nature Geoscience, that felt causally under my attention (referenced here). Some preliminary thinking of mine is also in this  invited poster at EGU 2010.

Last, but not least, ecohydrology has an important role.  There is a persistent trend among fluvial geomorphologists (BTW this is "another" geomorphology type) to consider the effects of vegetation on creation of meanders, bars, and forms. These effects are lived by geographers in the qualitative mood of taking pictures, doing surveyings, writing long an beautiful descriptions, but my shallow opinion is that all of  it could be pursued more quantitatively, by doing models. 
On this topic,  this paper criticised the assumptions of a paper of mine (Ignacio's, Andrea's, Bill's) modeling, I think with some argument.  Vegetation, therefore should be included in new models.

Coming to  more practical arguments, I was a producer of conceptual models. That story is well documented. Instead looking for more process based models, l can remind the one developed by Gary Wilgoose (see here) with Raphael Bras. While the main actor in developing it was certainly Greg Tucker, Raphael was certainly involved also in the development of CHILDS, another remarkable example of modelling, which can be taken as null hypothesis for any further development (it contains also a treatment of vegetation, but I doubt of the cryosphere). 
I have to warn that the above models are mostly of the fluvial transport type of models, and they do not embed many of the features I listed as relevant above. So, definitely there is a lot of room for new works and developments. 

* - Well, I think that the work of Stefano Orlandini on the detection of drainage directions, and arrived recently, is important and definitive. But sooner or later I will do a more detailed post on the subject of "geomorphometrical" tools.

Wednesday, February 10, 2016

Some rules for new developments

After a meeting happened yesterday, the GEOframe developers decided the following:

1)  All new development on NewAGE will go into the GEOframe repository. There will be no version 2.0 but evolution of old components and creation of new interoperable components.

2)  It is (not mandatory but) suggested that any development of a new component should be announced in the geoframe developers' google group. Any modified component will be developed in a branch where every modification and innovation will be described by accurate commits.

3) At the end of the development , after an appropriate discussion through the developer googlegroup, a merging  with the base version will be made, and announcements will be given to the GEOframe users' googlegroup.

4)  Authors of modified components are the original authors and who makes the modifications.

5) Documentation, examples, jars, sim files, will go into a parallel repository (repo) indexed and referred on the geoframe blog. Standard documentation remains on geoframe blog following the standards. 

6) Code documentation rules and standards are going to be defined.