WHITEOUT frosts over the weekend, reminiscent of September two years ago, have farmers across a wide swathe of the Central Wheatbelt concerned about crop damage.
The eastern Wheatbelt was once again hardest hit by temperatures down to minus 4.3 degrees Celcius at 6am on Saturday at Newdegate and down to minus 2.9 again there on Sunday morning.
Saturday morning was the coldest it has been at Newdegate since the Bureau of Meteorology (BoM) started recording minimums there 20 years ago.
Farmers hardest hit by frosts which destroyed crops at the critical flowering stage two years ago in the Narembeen-Ardath area may have dodged a bullet this time, but those immediately to their west and further south at Hyden through to Newdegate and Nyabing appear to have again borne the brunt of the heaviest frosts.
Department of Primary Industries and Regional Development (DPIRD) weather station data recorded minus 4.4 at Nyabing, -4.1 at Babakin, -4 at Kulin and Belka East, -3 at Beverley East and -2.7 at Darkan on Saturday morning.
BoM recorded -3.2 at Corrigin, -2.4 at Hyden, -2.3 at Wandering and -2.2 at Collie East on Saturday.
A critical factor for crop damage, the duration of heavy frosts in the eastern Wheatbelt on Saturday morning was up to eight hours, with the temperature at Newdegate dropping below zero at 11pm Friday and still below zero at 7am Saturday.
That was an extreme case, according to BoM data, but most frost-affected areas saw a whiteout lasting from 1.5 hours on the fringe of the main areas to more than 3.5 hours in a strip from Salmon Gums through to Brookton and Beverley.
Although Cunderdin airport recorded -1.7 at 6.30am Saturday, the Great Eastern Highway appears to have been the northern boundary of the frosts, with crops further east at Merredin, Narembeen and out to Southern Cross unlikely to have been severely impacted by temperatures that approached zero or only briefly dipped under.
Frosts were generally less severe on Sunday morning with temperatures across the southern Central Wheatbelt south of the Great Eastern Highway generally ranging from zero to about -2.
The Sunday morning frosts were also of shorter duration, generally less than two hours indicated by BoM temperature data.
One exception was York on the western Wheatbelt fringe where BoM data indicated the temperature dropped to -1.5 about dawn on Saturday but was down to -2 on Sunday morning.
Perth BoM duty forecaster Tisha Winstanley said on Monday clear skies and light winds, coupled with the low temperatures over the weekend and into this week, contributed to the frosts.
“We had clear skies across the agricultural region and very, very light winds from the north and north east which meant they did not contain much moisture so we had frosts instead of a dew,” Ms Winstanley said.
“They (frosts) were right under the ridge (of high pressure) as it passed through.”
The risk of further frosts was expected to diminish as the week progressed into warmer weather.
BoM was predicting cloud cover, expected to reduce the risk of frosts over most of the Central Wheatbelt, for the early part of this week and this weekend, with a chance of showers on Sunday.
On the clear days it was predicting minimum overnight temperatures down to 20C in a few areas but more widely in the 5-7 degree range.
Scott Crosby, Nyabing, was one of several farmers to post frost reports at the weekend on the WA Wheatbelt Rainfall Facebook page.
“We found stem frost in the boot yesterday (Saturday) in our crop and barely flowering or out in ear but there is still wide spread damage,” Mr Crosby posted.
Another Nyabing farmer Mark Patterson admitted dodging a bullet but was grateful for the late break to the season and slow germinations.
“We only got down to just below zero here and there’s only one paddock I’m worried about,” Mr Patterson said
“But it won’t be until a week or two until we really know the extent of any damage.
“Some of my neighbours copped a bit but we should be OK from this event.
“We had about four really bad frosts in the past and they have happened towards the end of the month and into the first week of October so we’re not out of the woods yet.
“The crops are looking really brilliant but it’s drying out fairly quickly so we need a soft finish and about 15mm of rain, that would be brilliant.”
At Kojonup, Peter and Emily Hill were counting their blessings that cereals crops were only at flag leaf stage.
“Fortunately the crops were out late,” Ms Hill said.
“It got really wet around here so that held the crops back too.
“I’m sure the canola got touched up a bit and we’ll have a look later in the week but we won’t know the full extent of any damage until we harvest the crop.
“We’ve still got a full soil profile so it would be good to get a week or two of sunshine.
“But we will still need a finishing rain and hopefully we can finish with a good result.”
Last weekend’s frost brought memories flooding back for Newdegate farmer Ash McDonald.
“In 2016 we got smacked with our barley but last weekend it was plus three here, so we’re OK,” Mr McDonald said.
“The crops were late so we don’t have anything in ear, not like 2016.
“I guess the positive for frost-affected crops is that they can be cut for hay and there’s a shortage at the moment.”