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Daily Beach Watch Reports
Filed by
Bill Sargent
May 1
Yesterday's observation about snow fencing seems to hold true for the apparent erosion pauses we saw in January, February and March. They were at least partially caused by snow fencing and pallettes embedded in the beach.
The good part of this is that we can expect to see an apparent slowing of erosion as we enter the heavily strengthened Kelley and Thayer beach sites. The bad part is that there appears to be little change in the hydraulics of the system. The ocean will continue to spill into the deep channel behind the outer beach. Until this changes we can expect the beach to continue to erode to the north. We will see a slowing of erosion as the season progresses, but we may not see the beach starting to grow until well into the summer if at all.
April 30
The end of the beach now has two tips, with an overwash area between them. Rapid erosion is occuring to the more landward tip which is not hardened with snow fencing. Erosion is substantially slower on the eastern tip which is embedded with a four foot underground spine of pallettes and snow fencing. Full report tomorrow.
April 29
9:25 AM Too foggy for camera use. An interesting observation: the pauses we have been seeing might be partially caused by erosion being slowed by areas that have been strengthened by deeply embedded snow fencing. I will be trying to confirm this in the next few days. Erosion continues at about 6 feet a day and this section of the beach appears to have little fencing.
April 28
Town hall camp has been relocated about 100 feet north and appears to sit closer to the bay. It is now about 140 feet from the point. The Southernmost tree is 40 feet from the point and
Hammatt's camp is about 625 feet from the point. Erosion continues at about 6.2 feet a day (see Eldredge 4/26 survey) The concern is that the point at which the beach turns toward the bay also continues to creep north at about the same amount. This potentially threatens the northern camps. We hope the beach will start rebuilding before this becomes a serious concern.
April 27
At 12:20 it looks like people are preparing to move Town Hall. Point less than 60 feet from camp. Will switch to using two Christmas trees that Thadd placed 100 feet apart for visual referance for new readings.
Christopher's April 24 aerial photo may show why erosion continues. The broad plateau of sand that stretched from the tip south to Fred Truelove's old camp site appears to have been reshuffled so deeper water allows currents and waves to get close to the beach and continue to erode the tip.
During pauses, subtidal sand bar had been offering some protection. Much of that sandbar has now shifted around to the west further constricting the old deep water channel that runs just inside and parrallel to the outer beach. (see April 24 aerial photo.) Thanks Chris & Tim!
April 26
6:55pm post high tide
Appears outhouse is gone, 9 feet from Town Hall camp, 60 feet from end of point. Thanks Thadd for replanting Christmas tree! See Thadd's updated survey tomorrow.
April 25
As can be seen on Kelly Herbert's daily photo, high tide waves can now strike John Kelley's back building outhouse and are about 10 feet from the Town Hall camp itself. Most trees have been swept away, only two major ones are now visible. Though tide heights are still decreasing and no storms are in the forecast, erosion continues to be about 7.5 feet a day. We can expect waves to remove the back building and start hitting the camp itself in the next few days. Thank you for your photo Kelly!
April 24
Several trees have washed away behind Town Hall camp. Waves have apparently hit the back deck. We can expect this to continue for the next few days. We have averaged about 7.5 feet of erosion a day over the past week of relatively calm weather and low tide heights.
April 23
Erosion alert:
The tip of the beach continues to erode at a surprisingly fast clip. Now only about a hundred feet to Town Hall. One of the trees behind the camp also appears to be getting hit by waves, so high tide must be less than 15 feet from his deck. The camp probably has 0 days at severe erosion, 1 day at moderate and 2 days at 7.5 feet of erosion and 4 at under 7.5 days of erosion. Is anyone going to be taking aerials this week at low tide. They could help tell us if the inlet channel has moved and is driving some of this continued erosion. See daily shots for comparisons of trees and distance to point.
April 22
Switching to a more accurate reference Thayer flag to Kelley flag (70 feet) there is about 100 feet from Town Hall camp to the end of the beach.
April 21
Town Hall camp about 15 feet from ocean and 140 feet from tip of point. Profile at tip of point shows erosion continuing at around 7.5 feet per day.
April 20
"Town Hall" camp to ocean. 1 day at 30 feet, 2 days at 15 feet, 4 days at 7.5 feet. Hammatt camp to ocean. 14 days at 6 feet, 28 days at 3 feet, 56 days at 1.5 feet. Hammatt's camp to point about 700 feet.
These are based on visual estimates, will have exact measurements after next weekend.
April 199
Town Hall camp now about 170 feet from tip of North Beach. Average rate of erosion about 7.5 feet per day from the Inlet side.
April 18
Erosion forecast:
As high tide approaches the tip of North Beach is continuing to be pounded by 5-8' waves. So far the point is remaining steady. The average rate of erosion which had been 16 feet for the past two weeks had decreased to just under 7.5 feet during the last week. It is possible these long period waves will also be bringing in sand to thicken the point subtidally. I will have to wait until high tide passes to see the final configuration of the beach to determine the net loss or gain. If we see the trees behind Kelley's Town Hall camp start to disspapear we will know waves are within about ten feet of his porch.
At lower tide tip of point is presenting more of a sloping non-erosive profile. Appears to be some subtidal thickening. So while there is still some erosion on every tide there is also some thickening.
April 17
Despite long period waves point erosion appears to have paused. Town Hall still 180 feet from the tip and presumably about 40 feet to the ocean.
Still 1.5 days at 30 feet, 3 days at 15 feet, 6 days at 7.5 feet. Average rate of erosion appears to have been under 7.5 feet for the past few days.
April 16
Starting today I hope to start posting the daily reports on
Tim's North Beach website,
www.chathamnorthbeach.com, and only send e-mails in the
event of important changes. Anyone who wants to opt out of
getting e-mails, now is the time to let me know. Good news, Thadd tells me that the town has started pouring concrete for a
town camera.
Weather and waves expected to remain calm and low. Point remains
steady at about 180 feet from "Town Hall" camp.
Wave Alert:
I know I promised to shorten my reports.... But we have a wave
alert for 5-8 foot high long period waves starting today, worst
swells Thursday and peaking on Friday. Winds moderate NE
Thursday, becoming North Friday, before the system drifts East.
Our meteorologist predicts the waves will probably be higher
than the computers presently forecast. Fortunately tides will
only be 4.7 feet high during those days.
April 15
Today is calm with continuing tide height declines. "Town Hall" has 1.5 days
at 30 feet of erosion, 3 days at 15 feet of erosion, 6 days at 7.5 feet of
erosion and 12 days at 3.5 feet of erosion. This is half a day longer than
former estimates because it is based on Thadd's GPS measurements taken on
Sunday.
April 14
Erosion Forecast:
Using the average amount of erosion for the northern camps over the past 15
days. Hammatt's camp has about 16 days at 6 feet of erosion, 32 days at 3
feet of erosion and 64 days at 1.5 feet of erosion..
We can expect, however, that the past 15 days were the extreme and that the
beach may start building during this next week of calmer weather and lowertides. This will move the forecast to the upper end of the window. These
figures are provisional but indicate that the camps have a siginificant
chance of making it through the upcoming transition to summer and more years
on the beach.
April 13
From preliminary reports it appears that Town Hall camp has
about 1 day of 30 foot erosion, 2 days of 15 foot erosion, 4
days of 7.5 foot erosion and 8 days of 3.5 foot erosion from the
East and about 6, 12 and 24 days from the south. The good news
is that the tides are now below 5 feet and dropping. Will not
rise above 5 feet until early May. Will be a far smaller window
of high tides in May. Will know more when Thadd finishes his
survey. Urge everyone to open it as soon as it is posted.
April 122
Forecast: "Town Hall" camp to tip of beach. Six days at 30 feet
of erosion, 12 days at 15 feet and 24 days at 7.5 feet. Would be
good if someone could pace off the distance between Thayer and
Kelley flagpoles.
Another observation. For the last few months, the parrallel lines of well buried snow fencing have marked the end of the
beach. They appear to have acted as a 4 foot deep spine to
strengthen the beach and slow down even the severe erosion we
have been encountering.
April 11
Lower waves and wind today. "Town Hall" is still about 200 feet from tip of
beach. Also a platform of sand building subtidally. It is interesting that
it is more difficult to make predictions in this transition stage. During
the winter we had positive feedback that made it easier to gauge daily
erosion. Now we have more negative feedback between forces for erosion and
accretion. Somthing to remember for future years. Is anyone planning to make
surveys or take aerials in the next few days? Bill
April 10
Have lost another 20-30 feet off tip of beach, now between 180
and 210 feet from "Town Hall" to end of beach, moderate waves,
5.5 foot tides.Does anyone have direct observations from today? Another use
for this site yesterday I asked if anyone could give me a ride
down the beach. Had two offers in less than a minute!
April 9
Things look somewhat calmer today. Today is the last 5.7 foot
tide of the month. Town House is still about 1 day of 30 foot
erosion, 2 days of 15 foot erosion and 4 days of 7 foot erosion
from high tides. These are estimates based on observations from
last weekend. The camp is now about 210 to 240 feet north of the
inlet. I know it is difficult to have your camp singled out this
way, but it is the quickest and most efficient way to determine
what is going on.
Note: Could anyone give me a car or boat ride down the beach on
Saturday April 19th?
April 8
Sad to report that Kelley's Outhouse appears to have been lost during last
night's high tide cycle. This may have been from overwash. The next camp
John Kelley's "Town Hall" is about 13 days of severe erosion from the inlet,
but may be only 2 days of severe erosion, 4 days of moderate and 8 days of
slight erosion from the oceanside. I need first hand beach reports from the
beach, because I cannot see east to west erosion. On the other hand there
appears to be a lot of subtidal sand off the tip of the beach, that could
provide a platform for growth once we get beyond this transition stage. This
is still a system in considerable flux.Note on forecast methodology: If you look at Alan McClellan's photo on the home page of the north beach website you can see how we determine erosion windows. The face of each camp is about 30 feet long. I pace that out and use that as a measuring stick to count out distances to the end of the beach. Severe erosion has averaged about 30 feet a day, moderate erosion about 15 feet, and slight erosion about 7 feet and minimal erosion under 3.5 feet. The Inletcam allows us to focus in closer on details. During times when decisions have to be made I try to achieve accuracy down to about 7 feet, during foggy conditions or in less important times I try to be within 10 to 20 feet. These forecasts provide daily snapshots that can then be ground truthed with greater accuracy by using GPS measurements and aerial photos.
April 7
Strong winds and high waves have caused expected heavy erosion to the tip of
North Beach. Wind and waves should drop off quickly after today's high tide,
but we still have to contend with over 5 foot tides until Sunday the 13th.
Forecast: 5 days of heavy 30 foot erosion, 10 days of moderate 15 foot
erosion and 20 days of 7.5 foot erosion between Kelley's outhouse and tip of
North Beach.
April 6
Hi All,
I also want to urge you to check out Tim's site. He will be posting
my forecasts including the raw data that they are based on. We hope
that he will soon be able to start including snapshots that will
show how we determine erosion rates visually.
Tonight and tomorrow will continue to be stormy with moderate waves.
The rest of the week lows should stay well to the west of Cape Cod.
This should mean severe erosion will drop down to moderate erosion
during the middle of the week. At the same time we will be having
some of the highest tides of the year 5.6' to 5.7'.
After these conditions pass we may start to see the tip of the beach
thicken as it was doing last week. This back and forth oscillation
should continue until we enter the low energy season in late Spring.
The end of the beach is now about 7 days of 30 foot erosion from the
nearest structure (Kelley's outhouse?) 14 days of 15 foot erosion,
and 28 days at 7.5 foot erosion. Erosion appears to be continuing at
the same rates from the East as well.
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