diff --git a/src/proto_alpha/lib_protocol/src/roll_storage.ml b/src/proto_alpha/lib_protocol/src/roll_storage.ml
index bcfda72e3..a5d324d67 100644
--- a/src/proto_alpha/lib_protocol/src/roll_storage.ml
+++ b/src/proto_alpha/lib_protocol/src/roll_storage.ml
@@ -17,9 +17,15 @@ let get_contract_delegate c contract =
   | Some manager -> return (Some manager)
   | None -> Storage.Contract.Delegate.get_option c contract
 
+let get_contract_delegate_at_cycle c cycle contract =
+  match Contract_repr.is_default contract with
+  | Some manager -> return (Some manager)
+  | None -> Storage.Contract.Delegate.Snapshot.get_option c (cycle, contract)
+
 let clear_cycle c cycle =
   Storage.Roll.Last_for_cycle.delete c cycle >>=? fun c ->
-  Storage.Roll.Owner_for_cycle.clear (c, cycle) >>= fun c ->
+  Storage.Contract.Delegate.delete_snapshot c cycle >>= fun c ->
+  Storage.Roll.Owner.delete_snapshot c cycle >>= fun c ->
   return c
 
 let fold ctxt ~f init =
@@ -37,16 +43,10 @@ let fold ctxt ~f init =
   loop ctxt Roll_repr.first (return init)
 
 let freeze_rolls_for_cycle ctxt cycle =
-  fold ctxt (ctxt, Roll_repr.first)
-    ~f:(fun _roll contract (ctxt, promoted_roll as acc) ->
-        get_contract_delegate ctxt contract >>=? function
-        | None -> return acc
-        | Some delegate ->
-            Storage.Roll.Owner_for_cycle.init
-              (ctxt, cycle) promoted_roll delegate >>=? fun ctxt ->
-            return (ctxt, Roll_repr.succ promoted_roll))
-  >>=? fun (ctxt, last_promoted_roll) ->
-  Storage.Roll.Last_for_cycle.init ctxt cycle last_promoted_roll
+  Storage.Contract.Delegate.snapshot ctxt cycle >>=? fun ctxt ->
+  Storage.Roll.Owner.snapshot ctxt cycle >>=? fun ctxt ->
+  Storage.Roll.Next.get ctxt >>=? fun last ->
+  Storage.Roll.Last_for_cycle.init ctxt cycle last
 
 (* Roll selection *)
 
@@ -69,8 +69,19 @@ module Random = struct
     let rd = level_random random_seed kind level in
     let sequence = Seed_repr.sequence rd (Int32.of_int offset) in
     Storage.Roll.Last_for_cycle.get c cycle >>=? fun bound ->
-    let roll, _ = Roll_repr.random sequence ~bound in
-    Storage.Roll.Owner_for_cycle.get (c, cycle) roll
+    let rec loop sequence =
+      let roll, sequence = Roll_repr.random sequence ~bound in
+      Storage.Roll.Owner.Snapshot.get_option c (cycle, roll) >>=? function
+      | None ->
+          loop sequence
+      | Some contract ->
+          get_contract_delegate_at_cycle c cycle contract >>=? function
+          | None ->
+              loop sequence
+          | Some delegate ->
+              return delegate
+    in
+    loop sequence
 
 end
 
diff --git a/src/proto_alpha/lib_protocol/src/storage.ml b/src/proto_alpha/lib_protocol/src/storage.ml
index b5608b222..fae5e39e5 100644
--- a/src/proto_alpha/lib_protocol/src/storage.ml
+++ b/src/proto_alpha/lib_protocol/src/storage.ml
@@ -70,8 +70,10 @@ module Contract = struct
       (Make_value(Bool))
 
   module Delegate =
-    Indexed_context.Make_map
-      (struct let name = ["delegate"] end)
+    Make_indexed_data_snapshotable_storage
+      (Make_subcontext(Raw_context)(struct let name = ["delegate"] end))
+      (Cycle_repr.Index)
+      (Contract_repr.Index)
       (Make_value(Ed25519.Public_key_hash))
 
   module Counter =
@@ -143,14 +145,6 @@ module Cycle = struct
       (struct let name = ["last_roll"] end)
       (Make_value(Roll_repr))
 
-  module Roll_owner =
-    Make_indexed_data_storage
-      (Make_subcontext
-         (Indexed_context.Raw_context)
-         (struct let name = ["roll_owners"] end))
-      (Roll_repr.Index)
-      (Make_value(Ed25519.Public_key_hash))
-
   type nonce_status =
     | Unrevealed of {
         nonce_hash: Nonce_hash.t ;
@@ -247,12 +241,13 @@ module Roll = struct
   module Contract_change = Contract.Change
 
   module Owner =
-    Indexed_context.Make_map
-      (struct let name = ["owner"] end)
+    Make_indexed_data_snapshotable_storage
+      (Make_subcontext(Raw_context)(struct let name = ["owner"] end))
+      (Cycle_repr.Index)
+      (Roll_repr.Index)
       (Make_value(Contract_repr))
 
   module Last_for_cycle = Cycle.Last_roll
-  module Owner_for_cycle = Cycle.Roll_owner
 
   let clear = Indexed_context.clear
 
diff --git a/src/proto_alpha/lib_protocol/src/storage.mli b/src/proto_alpha/lib_protocol/src/storage.mli
index 843c74818..eb368d714 100644
--- a/src/proto_alpha/lib_protocol/src/storage.mli
+++ b/src/proto_alpha/lib_protocol/src/storage.mli
@@ -25,8 +25,9 @@ module Roll : sig
   (** Storage from this submodule must only be accessed through the
       module `Roll`. *)
 
-  module Owner : Indexed_data_storage
+  module Owner : Indexed_data_snapshotable_storage
     with type key = Roll_repr.t
+     and type snapshot = Cycle_repr.t
      and type value = Contract_repr.t
      and type t := Raw_context.t
 
@@ -70,11 +71,6 @@ module Roll : sig
      and type value = Roll_repr.t
      and type t := Raw_context.t
 
-  module Owner_for_cycle : Indexed_data_storage
-    with type key = Roll_repr.t
-     and type value = Ed25519.Public_key_hash.t
-     and type t = Raw_context.t * Cycle_repr.t
-
 end
 
 module Contract : sig
@@ -107,8 +103,9 @@ module Contract : sig
      and type t := Raw_context.t
 
   (** The delegate of a contract, if any. *)
-  module Delegate : Indexed_data_storage
+  module Delegate : Indexed_data_snapshotable_storage
     with type key = Contract_repr.t
+     and type snapshot = Cycle_repr.t
      and type value = Ed25519.Public_key_hash.t
      and type t := Raw_context.t