Managing Weather and Climate Variabilities
The concept of spring, summer, autumn, and winter, four evenly spaced and timed seasons, is an English construct that is totally inappropriate for the Australian climate. Throughout Australia, we experience several seasonal patterns. At Eaglerise Farm we are guided by the traditional owners of the land, and we have developed our own understanding of seasons and their impact on our landscape. You can find more detailed descriptions of indigenous weather knowledge on the Bureau of Meteorology site.
Australia, being in the southern hemisphere, has weather patterns have a regular cycle of high-pressure systems traversing the country from west to east. Our high pressure systems rotate anti-clockwise. In southern Australia, these highs are followed by low-pressure systems (rotating clockwise) coming up from Antarctica. Mid-year the highs cross the country further north. This allows the low-pressure systems to have greater impact on our weather in southern Australia. During the long-day season, November to March, the highs move across the country further south. These push the low-pressure systems south with subsequent lower impact on Eaglerise Farm weather.
When the high-pressure systems traverse Australia along their southerly route, they interact with series of intense lows moving from east to west, south of the equator through the top end of Australia. It is these lows that often intensify into tropical cyclones.
The Australian Government provides for the Bureau of Meteorology to record all our weather data. The closest weather station to Eaglerise Farm is at Albury – 35km away to the south. Official, specific, detailed data is of limited value when it comes to designing and managing a farm. Following permaculture principles, we need to have a good understanding of the patterns so we can design our farm to cater for variable details.
Here, we have the maximum and minimum temperatures. There is a considerable variation. Well-designed farms need to be robust enough to cope with the fluctuations throughout the year in addition to the fluctuations between years.
The variation in rainfall is considerable too. Water conservation and wise use is an Australian norm. Plant species need to be selected to get through the dry times and still have sufficient drainage for the wet seasons. The lowest rainfall statistics demonstrate a worst-case scenario and how critical water conservation is and how we need to capitalise on maintaining soil moisture. This worst-case scenario is, unfortunately, far too common an occurrence.
The mean number of cloudy days reflects the growing season and the lower soil temperatures we experience from May to September. The number of clear days corresponds to the hot, dry season from December to early April.
The Seasons at Eaglerise Farm
When you combine this data, you start to see some dramatic possibilities for the weather at Eaglerise Farm. We have designated several seasons that may or may not present each year! The length of each season is not fixed. All is determined by the prevailing weather pattern. The driver here is the permaculture principle of designing from patterns to detail. We look at the patterns in our weather and determine what particular detail is appropriate to remediate possible consequences.
It is important to note that these seasons are solely applicable to Eaglerise Farm. They are not meant as a recipe for any other place. True understanding comes from observing your own weather patterns and noting their effect on your farming system. What we have here is a system to alter for your place. You get to name and describe your own seasons. When you do this, you take ownership and responsibility for your decisions.
The Hot Dry
Over December to April, we can experience:
- more than a third of the time to be clear days.
- Virtually no rain
- Daily temperatures from 35 to 44 degrees Celsius.
The temperature outside our backdoor during the 2019/2020 drought
This presents a season that I call the “Hot, Dry”. During this time of the year, high pressure systems tend to be centred over the middle of the country. This still air allows the interior to become super-heated and Eaglerise Farm to experience hot days with clear skies. As this weather pattern moves to the east, Eaglerise Farm is made subject to northerly winds that blow the heated air south to an already hot, dry environment. These northerly winds often gain strength from a low-pressure system coming across from The Great Australian Bight, that then turn into a south westerly change.
The farm dries out and the pasture can turn brittle underfoot.
Management for this season includes bushfire protection. We have designed the farm based on permaculture’s sector analysis. Eaglerise Farm has a southerly aspect. Any fires ignited in front of these northerly winds will slow as they move down the slope. We have our main laneway on the north side of the house, and this acts as a firebreak. The driveway comes up a ridge to the southwest of the house and this presents as a firebreak for any fire fanned by the south-westerly wind change. The house is a straw bale construction, which is very fire resistant.
This season also presents as very low soil moisture and high soil temperature, no pasture growth, reduced soil biological activity, stock requiring increased water and shade, our chickens seek shelter and reduce their foraging and laying rate, and difficulties in the market garden with maintaining sufficient irrigations and reducing wilting of the vegetables.
Early in the Hot Dry, the acacias have seed ready to harvest. We collect this seed to broadcast throughout our revegetation areas to boost the percentage of low and medium shrubs. Some of this seed is trailed along our swales to firm them and increase our paddock diversity.
Our bees often stress in the heat and can be seen fanning the front of the hives. If we have any pigs left, they stress in the heat and spend their days wallowing and laying in the shade. This does not suit our pig production model.
To manage these difficulties, we are repairing our main dam to reduce leakage and sinking a bore to enable water security. We have selected species suitable for a low water enterprise.
We are building living tunnels to provide dappled shade for allocated vegetables as well as a harvest from the vines growing over them.
Rufous Songlark trill as they proclaim their presence across the landscape. Australian Ravens wail from their perches and Wedgetail Eagles soar on the thermals produced by the hot weather. Another classic in the Hot Dry is the Cicada. They sing us to sleep every night. We see increasingly more reptiles as they warm up and hunt for food.
Our strawbale house demonstrates its design with no sunlight hitting the north facing walls. The eaves shade the house, and the pergola shades the areas around the house. The internal thermal mass only slowly absorbs the heat. We sometimes spray a mist over the mudbrick to act as an evaporative cooler. If we get a cool spell, in the evenings we open our doors and the clerestory windows to vent the warmer air at the ceiling area.
Our solar power system provides excess power. This enables us to use many electrical appliances. We have our food dryer on most days and cook using our BBQ or our small, benchtop electric oven.
The hot, dry season presents our most challenging season to manage.
The Wet, Hot, Dry
This normal transition of high- and low-pressure systems is sometimes thrown into disarray. Australia can experience an East Coast Low slowly moving south. These clockwise rotating systems are slow moving and can bring in moist air over the Great Dividing Range to subject Eaglerise Farm to a few days of easterly winds and rain. During the hot, dry season they are commonly formed from ex-tropical cyclones as they break down and move south.
Occasionally, the low-pressure systems coming up from the Antarctic in the southwest, can intensify and move north a bit more. This can produce a considerable rain event within the normally Hot Dry season.
These two examples can drop up to 50mm of rain over a day or two. I like to call this event the Wet, Hot Dry season. It may last from a day to a week, resulting in:
- an unseasonably higher soil moisture level that can promote vigorous pasture growth from our native grasses.
- A germination event of seasonal weeds in any area that may have been subjected to a disturbance, such as, inadvertently over grazed.
- An increased likelihood of an internal parasite issue with the livestock, especially Barber’s Pole Worm in the sheep.
- Increased humidity in the vegetable beds and the fruit trees will make them more susceptible to pathogen and insect attack.
- A respite from impending bushfire danger and a personal respite from the heat.
- Washing out of nectar from any flowers- wild and domestic, thus reducing the resources for the bees.
- A top-up of our rainfall tanks from roof runoff, and our seasonal spring may recommence to flow and fill our stock water tanks. This provides relief from pumping every few days and reduces fossil fuel consumption.
- The increased humidity can instigate a wave of myxomatosis through the rabbit population.
- A flurry of activity from our native bird population as they enjoy a break from the intense heat.
We determined several management practices for this event.
- Increase stock checks and rotational, cell grazing.
- Incorporate any weed issues into the grazing plan or monitor the germination to observe the seedlings drying up as the Hot Dry season recommences.
- Prepare some compost tea to increase the diversity on the vegetables and fruit trees to reduce the likelihood of any pathogen becoming dominant.
- Leave the hives in peace until there is a fresh nectar flow.
A Wet, Hot Dry season presents a mixed result that gives some respite but also presents some challenges to monitor.
When the Pacific ocean temperatures are warmer in the central and eastern tropical areas, the air moisture moves eastward and Australia goes under an El Nino weather system. It is often accompanied with weaker trade winds. This is one phase of the El Nino-Southern Oscillation. South Americans named it El Nino as it often comes along with Christmas and El Nino means, the boy child. In Eastern Australia an El Nino is characterised as extended hotter and drier conditions. It intensifies heat waves, extends the dry season in northern Australia, reduces tropical cyclone frequency, and decreases alpine snow. There can also be an increased probability of inland frosts due to the clear nights. From our Eaglerise Farm perspective, it increases the possibility of an extended and extreme hot dry season, with minimal chance of rain.
Under these conditions, any pasture tends to dry out so much that it crunches as you walk on it. It requires serious consideration of stocking rates as the pasture contains minimal feed value. If stocking rates are maintained, there will be inflated costs in any bought in supplementary feed – hay, grain, pig/poultry feed, if it can be sourced. There is high probability that soil Carbon will reduce causing a flow on impact of short term feed availability, even after the season passes.
The Crunch also coincides with increased fire danger. It presents the dilemma of reduced feed availability, but increased need to manag dry feed in firebrakes.
These conditions are exacerbated when they coincide with a positive Indian Ocean Dipole (IOD) event that will draw moisture away from Australia.
The Cooling Dry
As the high-pressure systems slowly transition to their mid-year latitudes, the low-pressure systems afford us relief from the heat. Around March-April we are able to get out and about and enjoy the bright days to get plenty of farm work done.
Somewhere here, often without us knowing, the Rainbow Bee-eaters congregate and migrate north. At some stage, we realise that we cannot hear them anymore. The Diamond Firetails can be seen flying around with nesting materials and we see them doing their courtship jigs on the branches.
Our chickens can go clucky here and we get some replacement chicks. Our olives are ready for harvest, and we assess the window of opportunity regarding the appropriateness of buying some early pigs to grow out before the Cold Wet.
The customer base at the Farmers’ Market starts to increase as the days become increasingly pleasant. This is a good season for evening BBQs.
The Cooling Damp
After the Cooling Dry, somewhere between April and May, we can experience an increased incidence of rain. This is a break in the season and increases soil biology activity which provides a germination event within our pasture, especially the clovers. If our grazing management over the Hot Dry has caused any small bare patches, they now get some cover. It is a chance to get some farm work done without the extreme heat and before the season turns cold and the days shorten.
The leaves are turning golden on the fruit trees and in the vineyard.
The soil moisture is increasing but the soil temperature is reducing too. This is the season to get plants established before the soil cools and reduces growth rates.
Whilst there is still some soil warmth, this is a good season to harvest field mushrooms and dry them for sale at the markets as seasoning.
With the decrease in bushfire danger, it is a good opportunity to get out and collect our firewood.
We hope our farm dams get enough runoff to fill, in preparation for the dry seasons. Much of the runoff is held back in our paddocks by our swales to increase soil moisture. However, at Eaglerise Farm, we have considerable area with exposed rock that gives ample runoff into our gullies.
The Early Frost
Whilst the high-pressure systems are slowly moving north, we can get occasional frosts. These are formed within the still air in the middle of the systems. It is worthy to note that we can see the intensity increase as we move down the slopes and away from the tree areas.
These photos were all taken on May 5 and clearly show the frost intensity reducing as I walked up the food, grassy woodland and into a tree area. Our living hoop houses provide shelter from these frosts and still allow any sunlight to get through.
If the preceding seasons have been optimal for Red Legged Earth Mites, then the early frosts tend to kill off any adults. The population can crash from alarming numbers to virtually nil in a few days. Some of the female mites have buried into the soil and deposited eggs for next year.
The Cold Wet
When the weather patterns have settled into their mid-year northerly aspects, Eaglerise Farm becomes susceptible to increased low pressure systems tracking from the west to the east. These bring cold air from deep south near Antarctica.
The East Coast Lows that initiate the Wet, Hot, Dry season are more prevalent in June. The tables show June/July to have increased cloudy days, increased likelihood of rain and lower temperatures. We like to call these dark, short days the cold, Wet season. The Cold Wet season can have maximum daily temperatures of only 8 degrees Celsius. It may last for a week to months. Although as we pass the shortest day on June 21, we experience a slow improvement.
Fogs often present. They may roll over the top of our hills, or, more commonly, they engulf our southerly neighbour’s farms and do not quite make it up to our house. We remain bathed in sunshine and our solar power system gets a good recharge.
The increase in soil moisture, combined with the easterly winds can loosen trees to the point of falling over. This often necessitates fencing repairs. The positive to this is that it will provide ample firewood for our heater and cooking.
The soil temperature has reduced enough to minimise any plant growth and the market garden is, mostly, in a state of hibernation. There can often be frosts. Fortunately, at Eaglerise Farm, the frosts are tempered by our site being on a slope where the cold air often slides down the slope to our neighbour. Fogs come and go, often only up to our southerly boundary before the slope banks it up. We appreciate being in the sun and looking over the fog below us.
Livestock need to be provided shelter from cold winds and, perhaps some supplementary energy source, such as hay. Any lambing ewes need careful attention to reduce the incidence of pregnancy toxaemia with the reduced quality of energy in the pasture. Lambing ewes need paddocks with long feed to provide short wind breaks for the newly born lambs.
Our egg production drops off as chickens moult in the short-day length. We experience an increase in dirty eggs. We use straw and shredded paper as nest material. When the hens’ feet are muddy, they bring it into the laying boxes. We monitor this and continually replace the nest material. The fouled material is put into the trailer for later composting.
This is a good season to avoid pigs. The cold reduces soil microbiology for feed and the pigs need increased energy to stay warm. Their growth rate decreases.
We keep our market lambs in a sheltered paddock all year. They get shade in the Hot Dry and shelter from the wind in the Cold Wet.
The Cold Wet season is one of casseroles and soups in front of the fire – a good season for reading and researching. Time to get financials sorted for the taxman. Our strawbale house proves itself with any sunlight streaming in through our north facing windows and high clerestory windows to warm our slate floor and mudbrick thermal mass walls. On any frosty day, the sun rises over our hills and, within seconds, brilliantly lights up the house through our windows. Our ceiling fans are set to move the air up to the ceiling then down the walls and the house remains very comfortable. The solar power system can struggle in this season, and we may consume fossil fuel in the generator to keep it topped up.
The low level sunlight streams through the clerestory windows and reflects down into the house. This brightens up the house and its inhabitants
We look forward to the arrival of our Hooded and Flame Robins and the Brown Falcons are maximising our ecosystem as they harvest food for their young. Our Farmers’ Markets tend to be supported by, mainly, our stalwart supporters.
Late in the Cold Wet is when we try to do any replanting or revegetation works. We try to get the plants in and protected with a wind/rabbit guard early so they can get established in the next seasons prior to the upcoming Hot Dry.
The Late Frosts
Although we can get frosts throughout the Cold, Wet, the weather pattern provides increased possibilities as the high-pressure systems move south. These late frosts can impact on any fresh seedlings in the market garden. We watch out for the bees and, generally, leave them alone until the season warms up more.
This is a season of anticipation as we await the soil temperature to increase so the soil biology reactivates and we can expect increased growth.
Sometimes it seems to come around in a hurry. The Wake-Up season celebrates the warming of the ecosystem from somewhere around August to September. The increase in soil temperature activates the soil biology and encourages plant growth. Everything from weeds to vegetables to pasture responds to this season. All the animals enjoy the longer days and warmer temperatures. Chickens lay more eggs and often get clucky again to give us new replacement chickens.
This is the season to buy our seasonal pigs. As the weather warms up, the pigs convert their feed into pork rather than using it to keep warm. We feed them surplus vegetables and eggs. The aim is to have them finished prior to the onset of the hot, dry season.
This is the season to watch out for bee swarms. Bee boxes need to be prepared for quick action to catch any swarms that may have been attracted to our apiary. This season may produce an early nectar flow. The hives need monitoring and robbing.
Here we have our bait box for any passing swarms
Our weather data shows an increased chance of heavier rainfalls around October. This presents our last big chance to fill our dams and soil moisture in our swales.
We have had some heavy rainfall events that have caused some washing of our driveway and anywhere else if we have not maintained ground cover. We, sometimes, call this the runoff season or the warming, Wet season.
It is important to design the farm to minimise erosion. Here is an example of poor design where we had to undertake some remedial work to the erosion down the track.
The Wake-Up season gives us a display of blossom after bud burst in our fruit trees, in our acacias and in the sub-clover in the pasture. Lots of activity. But beware of pollen allergies.
Between the Wake-Up and the Hot Dry, we have a Transition season. This Transition may be either wet or dry. It is highly variable. But as the high-pressure systems migrate south, pushing the lows further away, the Transition follows an increase in temperatures with or without storm events, as the days continue to lengthen. The high rainfall statistic in October indicates the possibility of some major rainfall events. It could easily be described as a warming wet season- a great season for farm picnics and sunrise breakfasts on the top of our hill.
After the blossoms in the Wake-Up season, the Transition gives a display of green leaves over our fruit trees and the vineyard. It extends the feeling of life and anticipation of bountiful harvests. Late in the Transition we see golden globes of fruit on our trees. We have selected for early varieties of fruit trees so we can harvest the fruit whilst there is adequate soil moisture and before the trees need supplementary irrigation and before the fruit fly can get too concerning.
This season keeps us alert for bee swarms and the bee season is in full flight with good nectar flows.
The chickens are busy eating insects, worms and laying plenty of eggs.
The grazing animals are responding to the improved pasture quality and quantity and grow well.
The market garden explodes with productivity.
We need our seasonal pigs here to convert the surplus eggs and vegetables to pork chops.
There is activity everywhere.
As the days warm up, we see increasingly more reptiles.
The end of the Transition and the start of the Hot Dry is indicated by the arrival of the Rainbow Bee-eaters. We see them all over the farm and enjoy watching their antics as they fly from their roosts in old trees and swoop around collecting insects for their young.
They nest on our earth banks, and you can see trails left by their long tail feathers.
The end of the Transition is characterised by the pasture drying off and the landscape shifting from green to golden brown. Our sense of optimistic, high productivity is sobered with the increasingly higher temperatures and the drab, drying off of the landscape.
This is also the start of the grass seed season where we need to keep an eye on our guardian animals for grass seed abcess and seeds in their ears. The problem comes from the many native species we have, especially in our hill paddocks. When we grew the merino type sheep, this was a serious issue, especially with lambs getting the native grass seeds in their bellies. We often had to shear off their belly woll to give them some respite from the constant irritation.
Somewhere near the end of the Transition and the Hot Dry, we collect seeds from the acacias for distributing around the farm.
Then we have the Hot Dry!