The Fraser River's levels are heading up, and local emergency planners began issuing the first heads-up warnings to those in the potential flood zone Monday.
Heavy rains in the Interior have swollen the Upper Fraser and late last week, flood warnings were issued for areas in and around Prince George.
Water levels near Langley spiked over the weekend as the water came down from the Upper Fraser.
From around 4.5 metres, the water level hit 5.189 metres on the Mission gauge by Monday morning.
As the level passed five metres, Langley Emergency Coordinator Ginger Sherlock and others began issuing notifications to residents in the Fraser floodplain, near Fort Langley, Allard Crescent, and Glen Valley.
Sherlock, members of the RCMP and other emergency service providers met Monday morning to talk about the situation, but the water is still far below the level where it could pose a serious danger even on the floodplain.
Water levels have hit as high as six metres in 2007, and again two years ago, without causing significant impacts. Water that high will flood some low-lying fields and campsites along the river.
"After six metres, we're starting to look at roads being impacted," Sherlock said.
Allard Crescent could be flooded out if water rises higher than that.
Much higher, and water will be on the dikes that protect much of the floodplain.
If that happens, emergency personnel will be monitoring the dikes 24 hours a day, watching for water seeping through or potential breaks.
On Sunday and Monday, water was creeping up towards the campsites at Derby Reach Regional Park, but had not yet caused Metro Vancouver to close the park.
Some low-lying fields around Allard Crescent and in Fort Langley were becoming waterlogged.
It's unknown if the current pulse of water will be the highest level of the year, or if the water will recede and rise again.
"It all depends on how quickly the snow melts," said Sherlock.
That will depend on how much rain and heat hit the B.C. Interior in the next few weeks. Mild weather means a slower melt and reduced risk of flooding anywhere in the Fraser River system.
The most recent May 15 snow report showed that there was very high snowpacks still remaining on some Interior mountains.
Parts of the Interior received up to 167 per cent of the average snowfall, while other areas, including parts of the Lower Fraser, received little more than the average.
According to Dave Campbell, head of the provincial River Forecast Centre, it takes between 2.5 and three days for water to make its way down from the Thompson and North Fraser rivers to the Lower Mainland.
He expects water levels could hit as high as 5.8 to 6.0 metres in the Lower Fraser this year.