Date: May 5, 2013
Crew: Robin Beebee and Mark Doner (HDR Alaska); pilot Alicen Bishop (Jayhawk Aviation)
Talkeetna Weather: Sunny, clear, temperatures varied from 28 to 46 degrees Fahrenheit (F), winds WNW less than 10 mph.
Objectives: Video Susitna River, observe breakup progress.
Data Collected:

Photos (JPEG) with GPS points
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Georeferenced video
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Open lead locations and open tributaries with GPS points
Summary: Breakup on the Lower River has not progressed past the intertidal zone
(approximately PRM 10), though meltwater was beginning to pool on the ice surface in many places. Fish Creek has opened up from Flathorn Lake to the Susitna River since April 25, 2013.
Tributaries along the east side of the Susitna were mostly open with significant leads where they meet the mainstem. In the last week, river stage has risen as much as a foot on the Lower River.
The Talkeetna and Chulitna Rivers have continued to open since the last survey.
On the Middle River, open leads have continued to expand; open water at sloughs and a slough mouth has increased significantly from April 25, 2013. Portage Creek, Indian River, and Fog
Creek remain mostly frozen. Devil Canyon was almost entirely open.
There was significant open water at the Kosina Creek confluence; however, the Oshetna River had not changed since January.
Flight Path: The team departed Merrill Field at 0900 hours and flew to the mouth of the Susitna.
They flew up the east side of the delta, back down the west main channel, then back up paralleling Alexander Slough to Alexander Creek. They then flew down to the mouth of Fish
Creek and up to Flathorn Lake. The team landed at an island across from Susitna Station to remount the video camera, the flew up the Yentna River approximately 5 miles, back to Susitna, up Deshka River approximately 5 miles, then returned to the Susitna River. They then flew along the Susitna River and then up Montana Creek approximately 5 miles, then back to the Susitna
River and to Talkeetna for fuel, then up Chulitna River approximately 2 miles above the confluence with Susitna, then returned to Susitna River and headed up the Middle and Upper
Rivers to the Oshetna River confluence. They returned to Willow via the direct route.
Lower River Observations
Mouth to Yentna River: Ice was largely stable on the mainstem of the Susitna River (Figure 1).
The Lower River remains ice covered above the intertidal zone, though there was more
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F IELD T RIP R EPORT S USITNA -W ATANA I CE P ROCESSES S TUDY meltwater pooling on the ice, which creates a positive feedback loop in the melting process
(Figure 2). Alexander Slough and Creek were still ice-covered with minor overflow and
discontinuous open leads. Fish Creek was mostly open from Flathorn Lake down to the Susitna,
then ice-covered down to the tidal flats (Figure 3, Figure 4). Flathorn Lake was still ice covered.
Pressure transducers show that the stage has risen about a foot in the last week at both Susitna
Station and Dinglishna Hill.
Yentna River: The Yentna was ice covered at the confluence and for about 5 miles upstream –
probably the rest of the way as well (Figure 5).
Yentna River to Talkeetna: The Deshka River was ice covered with minor overflow (Figure 6).
Rabideux Creek and Slough were open up to the highway crossing. The mouth of the Kashwitna
River remained ice covered. Tributaries from the east side, including Montana Creek (Figure 7),
Willow Creek, Sunshine Creek (Figure 8), and Birch Creek were mostly open, and there were
significant open leads at the confluences with the Susitna River. The Trapper Creek confluence and associated sloughs were also open. The pressure transducer at Twister Creek just downstream of the three-river confluence showed about 10 inches of rise in the last week, mostly in the last few days.
Talkeetna: Open leads at the three-river confluence have continued to grow, with some broken ice accumulating at the downstream end. The lower half-mile of the Chulitna River was largely
open, but ice-covered upstream of that with a few open leads (Figure 9). Much of the Talkeetna
River was open.
Middle River Observations
Open leads in the Middle River were expanding with additional overflow on top of the ice
between leads (Figure 10, Figure 11). There was an ice jam at Curry (PRM 123, Figure 12).
Open water at sloughs and slough mouths had increased significantly in the previous week
(Figure 13). Both Portage Creek and Indian River were largely ice covered, but more open leads
had formed at their confluences. Devil Canyon was almost entirely open with intermittent
bridges and jams (Figure 14, Figure 15). Fog Creek was mostly ice covered with little open water visible, yet overflow was present downstream of Fog Creek on the Susitna River (Figure 16).
Upper River Observations
There was a surprising amount of open water in Kosina Creek and at the confluence (Figure 17),
despite the fact that temperatures in the Upper River had only reached above freezing intermittently. The team flew upstream on the Oshetna to check for open leads, but the Oshetna
River did not appear to have changed significantly since January (Figure 18).
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F IELD T RIP R EPORT
Representative Photographs
S USITNA -W ATANA I CE P ROCESSES S TUDY
Figure 1. Ice cover in the intertidal zone at the mouth of the Susitna River, PRM 6.
Figure 2. Ice cover and meltwater on the Lower Susitna River facing downstream, PRM 30.
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F IELD T RIP R EPORT S USITNA -W ATANA I CE P ROCESSES S TUDY
Figure 3. Fish Creek and Flathorn Lake, PRM 18.5.
Figure 4. Tributary above Flathorn Lake, PRM 22.
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F IELD T RIP R EPORT S USITNA -W ATANA I CE P ROCESSES S TUDY
Figure 5. The Yentna River above the confluence with the Susitna, PRM 33.
Figure 6. One mile upstream of the Deshka River from the confluence with the Susitna River at PRM 45.
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Figure 7. Montana Creek, facing downstream. PRM 81.5.
Figure 8. Sunshine Creek, PRM 88.
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F IELD T RIP R EPORT S USITNA -W ATANA I CE P ROCESSES S TUDY
Figure 9. Chulitna River, PRM 102.
Figure 10. Overflow and open lead on the Middle River just above Talkeetna, PRM 107.
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Figure 11. Open Lead on the Middle River, PRM 120.
Figure 12. Small ice jam at Curry, PRM 123.
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Figure 13. Open water in slough downstream of Gold Creek, PRM 137.2.
Figure 14. Ice jam in Devil Canyon, PRM 154.
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Figure 15. Ice at the upper end of Devils Canyon, PRM 160.
Figure 16. Overflow on Upper River below, PRM 173.6.
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Figure 17. Kosina Creek confluence, PRM 209.
Figure 18. Oshetna River confluence, PRM 235.
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