Surat Basin weather for site work
The Surat Basin in southern inland Queensland is coal seam gas country: wells, pipelines and compressor stations spread across the plains around Roma, Wandoan, Miles and Chinchilla, supplying the LNG plants at Gladstone. There are coal mines too, such as Kogan Creek near Chinchilla and Cameby Downs near Miles. Summers are hot and humid enough to bring heat stress on most days, storms are common in spring and summer, and winter brings clear, frosty mornings.
The year at a glance
January highs average 33–35° and July nights 4–5°. Annual rain is 555–608 mm, and 63–64% of it falls from November to March, mostly from storms, rain bands and the odd tropical low. December is the wettest month in most towns, with about 90 mm on average, and February at Roma. Winter is the dry season, with about 20–35 mm a month from April to September, and July days are mild at about 20°.
| Town | January high | July low | Rain a year (mm) | Wettest month | Days reaching 40° | Heat-stress days |
|---|---|---|---|---|---|---|
| Roma | 35° | 4° | 555 | Feb 84 mm | 6 | 128 |
| Wandoan | 34° | 5° | 585 | Dec 91 mm | 4 | 148 |
| Miles | 34° | 4° | 608 | Dec 90 mm | 3 | 128 |
| Chinchilla | 33° | 4° | 572 | Dec 89 mm | 2 | 125 |
Heat and heat stress
Heat-stress days by month
| Town | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Roma | 28 | 24 | 21 | 5 | <1 | 0 | 0 | <1 | 1 | 8 | 17 | 24 |
| Wandoan | 29 | 26 | 25 | 8 | 1 | 0 | 0 | 1 | 3 | 12 | 19 | 26 |
| Miles | 28 | 24 | 22 | 5 | <1 | 0 | 0 | <1 | 2 | 8 | 16 | 24 |
| Chinchilla | 27 | 24 | 21 | 5 | <1 | 0 | 0 | <1 | 2 | 8 | 15 | 23 |
The heat here is humid rather than extreme. Roma reaches 35° on 54 days a year but 40° on only 6, yet it averages 128 heat-stress days, 35 of them at the stop level. Wandoan has the most, 148 a year with 43 at the stop level. Heat stress starts in October, with 8–12 heat-stress days, comes on at least half the days in November, and from December to March the caution level is reached on most days.
Toowoomba, up on the Great Dividing Range to the east, averages 46 heat-stress days and only 3 at the stop level, so crews coming from there or from the coast step up a long way in summer. These figures use the Bureau of Meteorology’s simplified formula, which assumes moderate sun and light wind, so read them as how often heat needs managing. The WBGT calculator and heat stress forecasts cover the details.
Storms and lightning
Thunderstorms are common across southern inland Queensland from spring into summer, often building through the afternoon. Some bring large hail and damaging squalls, and lightning stops work on well pads, pipeline spreads and open pits. Plant noise and wind make distant thunder easy to miss, which is why sites rely on detection: see lightning stand-down alerts.
Rain and floods
Most of the year’s rain comes in summer, and big totals can arrive in a few days. When they do, the Condamine River and the creeks through the towns can rise quickly, flooding low crossings and cutting the roads to wells, camps and pits. Clay roads turn to mud after heavy rain and can stay closed for days after it stops. More in rain, the wet season and haul roads.
Frost, fog and inversions
Winter is mild by day but cold at night: July averages 4–5° overnight, and frost is common on clear nights from June to August. Fog can form on still mornings and slow early starts on the roads. Those clear, still mornings also bring temperature inversions, which hold blast fumes and dust close to the ground: see blasting and temperature inversions.
Planning a year on site
- Put shutdowns, major lifts and long pipeline and earthworks runs into May to September, when heat stress is rare and rain is lightest.
- Plan for heat stress from October to March, and most of all from December to March.
- Have the lightning plan and shelters ready by October, before the storm season.
- After heavy rain, check crossings and clay roads before sending crews out.
- Allow for frost, fog and inversions on winter mornings when timing early starts and blasts.
Related: Queensland forecasts · Bowen Basin weather for site work · Rain, the wet season and haul roads · WBGT calculator